MXPA06009352A - Site-specific chemical modification of hiv gp41-derived peptides - Google Patents

Abstract

Provided is a method for site-specific chemical modification of an HIV gp41 -derived peptide, wherein during synthesis one or more amine groups of the HIV gp41 -derived peptide are chosen to blocked by a chemical protecting agent, and one or more amine groups are selected to be unprotected, and remain free to be reacted with an amine reactive functionality. The resultant HIV gp41-derived peptide may be used to produce a substantially homogeneous conjugate comprised of HIV gp41-derived peptide and polymer by covalently coupling the polymer to the one or more free (unprotected) amine groups of the HIV gp41-derived peptide.

Description

SPECIFIC CHEMICAL MODIFICATION OF THE HIV GP41 DERIVED PEPTIDE SITE FIELD OF THE INVENTION The present invention relates to a method for the specific chemical modification of the site of a peptide derived from HIV gp41 in such a way that, during the synthesis of the peptide, one or more amino acids having an amine group chemically protected with a chemical protective agent are added, allowing one or more of the selected amine groups of the synthetic peptide to be deprotected, so that they are chemically reactive ("free"). The resulting synthetic peptide can then be covalently coupled to an amine-reactive polymer by forming a substantially homogeneous conjugate composed of the peptide derived from HIV gp41 to which the polymer is covalently coupled at the specific site (s) and selected (s). BACKGROUND OF THE INVENTION It is well known at present that cells can be infected by HIV through a process by which fusion occurs between the cell membrane and the viral membrane. The generally accepted model of this process is that the glycoprotein complex of the viral envelope (gpl20 / gp41) interacts with the cell surface receptors on the membranes of the target cells. The next link of gpl20 to cellular receptors (e.g., CD4 in combination with a chemokine co-receptor such as CCR-5 or CXCR-4), induced is a conformational change in the gpl20 / gp41 complex that allows gp41 insert in the membrane of the target cells and the fusion of the mediated membrane. The amino acid sequence of gp41, and its variation between the different strains of HIV, are well known. FIG. 1 is a schematic representation of the accepted gp41 functional domains in general (note that the numbers of the amino acid sequence may vary slightly depending on the HIV strain). It is believed that the fusion peptide (the fusogenic domain) is involved in the insertion and disruption of the membrane of the target cells. The transmembrane domain, which contains the transmembrane anchor sequence, is located at the C-terminal end of the protein. Between the fusion peptide and the transmembrane anchor are two distinct regions, known as septete repeat (HR) regions, each region having a plurality of septets. The amino acid sequence comprising the HR1 region and the amino acid sequence comprising the HR2 region are highly conserved regions each in the envelope protein of HIV-1. The HR1 region, closest to the N-terminal end of the protein that the HR2 region, has been described as generally comprising the amino acid residues of SEQ ID NO: 1 or, polymorphisms thereof (see, for example , FIG 2). The HR2 region has been described as comprising the amino acid sequence residues of SEQ ID NO: 2, or polymorphisms thereof (see, for example, FIG 3). As shown further in FIG. 1, the HR regions have a plurality of stretches of 7 amino acid residues or "septets" (the 7 amino acids in each septet are called "a" to "g"), with a predominance of hydrophobic residues in the first ("a" ) and the fourth ("d") positions, residues frequently loaded in the fifth ("e") and seventh g ") positions, and with the amino acids in the" a "and" d "positions that are mainly determinants that influence the Oligomeric state and orientation of the strand It was discovered that peptides derived from the native sequence of either the HR1 region (the "HR1 peptides") or the HR2 region (the "HR2 peptides") of HIV gp41 inhibit transmission from HIV to host cells in both in vitro and in vivo clinical trials, for example, the HR2 peptides, which are exemplified by DP178 (also known as T20, efuvirtide, and Fuzeon®, SEQ ID NO: 3), T651 (SEQ ID NO: 4), T649 (SEQ ID NO: 5), block the infection of the target cells with potencies of 0.5 ng / ml (EC50 against HIV-11AI), 5 ng / ml (IC50, HIV-1 IIIB), and 2 ng / ml (IC50, HIV-1 IIIB), respectively. Efforts have been made to improve the biological activity of HIV gp41 derived peptides, such as, for example, to try to stabilize the helical structure of the peptide. Various efforts have also been made to improve the pharmacological properties of peptides derived from HIV gp41. Polymers have been used extensively to improve the pharmacokinetics and far-dinamodynamics (and therefore, pharmacological efficiency) of drugs such as peptides, proteins and small molecules. The most widely used polymer for pharmaceutical applications is polyethylene glycol ("PEG"). "PEGylation" is the process by which drugs are chemically modified to result in the covalent adhesion ("coupling") of one or more PEG molecules to the drug (depending on how many sites are available in the drug to interact with, and be conjugated to PEG). The improved pharmacological and biological properties associated with PEGylation of drugs are well known in the pharmaceutical art. For example, PEGylation can increase therapeutic efficiency by means including, but not limited to, reducing degradation by proteolytic enzymes and thereby increasing the concentration of the drug; increase the size of the drug to which it binds, thereby improving the biodistribution of the drug; and blocking antigenic epitopes by reducing immunogenicity, when desired. By increasing the therapeutic efficiency, the dosage frequency and / or the amount of the drug necessary to achieve a therapeutic effect can be reduced. PEG, as a linear polyether, has a general structure of: HO- (CH2-CH20) n-CH2CH2-OH where n may typically vary from about 10 to about 2000. PEG, as a branched polyether, has a general structure from: PEG-T-PEG I Z where T is a linker or molecular bridge that links the PEG molecules, and Z is the functional group with the chemically reactive portion. Many of the PEG modifications, by forming PEG derivatives (PEG and PEG derivatives are known in the art as "PEG"), are targeted to extreme groups ("functionalities") by adding or varying their chemical functionalities to be used when covalently linking the PEG molecule to a drug. Various PEG derivatives are well known in the art. To couple the PEG to a drug, typically a functionality of the PEG molecule needs to be activated to be chemically reactive. The type and specificity of the functionality are based on the choice of the group chemically reactive in the drug to which the PEG must be coupled. Most commonly for proteins and peptides, the chemically reactive group occurs in an amino acid selected from the group consisting of an internal amino acid having a side chain with a free chemically reactive group (eg, including, but not limited to lysine, cysteine, glutamic acid, serine, threonine and the like), the amino acid of the N-terminus (having an N-terminal amine group, or a side chain amine group, as a chemically free reactive group), an amino acid of the C-terminal (having a C-terminal carboxylic acid, or a side chain amine group, as a chemically free reactive group), and a combination thereof. Of the sites of a peptide to be coupled to PEG, the most frequently chosen is the N-terminal amine group ("alpha amine") of the N-terminal amino acid of the peptide, and the amine epsilon group ("epsilon amine") of a lysine (a lysine found in the amino acid sequence which is not the N-terminal amino acid or the C-terminal amino acid of the peptide) or an epsilon amine group of lysine when lysine occurs in a peptide as an amino acid of N-terminal or as a C-terminal amino acid.

Nevertheless, a problem arises this standard strategy for PEGylation. Lysine is one of the most predominant amino acids in proteins. When related to HIV gp41, there are multiple lysine residues in the amino acid sequence of the HR1 region and the HR2 region (see, for example, FIGS 1-3). respect to the peptide T20 derived from HIV gp41 (SEQ ID NO: 1), for example, there are two internal lysine residues in this peptide of 36 amino acid residues. Thus, a plurality of lysine residues in the amino acid sequence (consequently a plurality of side chain amines (epsilon amines) available to be reactive the activated PEG containing the reactive functionality amine) and an alpha amine, there are several sites to which the activated PEG can be covalently coupled the reactive functionality amine. The result of the standard PEGylation of such a peptide is a heterogeneous mixture consisting of a population of several conjugates that vary in the number of PEG molecules bound at the binding sites. The heterogeneity of such synthetic peptide-polymer conjugate is frequently an undesirable result. This is because the pharmacological and / or biological properties associated PEGylation of peptides may be dependent on factors such as (a) the number of PEG molecules linked to the peptide, and (b) the location of the sites on the peptide. to which the PEG is coupled. For example, the in vitro biological activity of the human growth hormone releasing factor depends on both the site and the degree of PEGylation. In addition to standard PEGylation, it is very difficult, if at all possible, to separate the species from the peptide-polymer conjugate ( the desired number of PEG molecules and the desired site (s) of linkage) of a heterogeneous mixture using conventional separation techniques known in the art. Such separation attempts to add to the cost, time, and reagents necessary to produce the peptide-polymer conjugate of the desired species. Several lysine residues in the amino acid sequence of a peptide to be PEGylated are perceived as such a problem that a method of site-specific PEGylation was developed which involves replacing the lysine residues amino acids other than lysine, and which lack a side chain threading a free amine. Therefore, in the formation of conjugates composed of a peptide derived from HIV gp41 (containing one or more residues of >; internal amino acids having a side chain amine in their amino acid sequence) and the polymer, there is a need for a site-specific modification of the synthetic peptide such that a synthetic peptide is produced which contains one or more amino acids having a side chain amine chemically protected with a chemical protective agent, and one or more amino acids having a free, unprotected amine available. Accordingly, a polymer can be covalently coupled only to a specific site, or specific sites, in the synthetic peptide, as selected by a person who performs synthesis and conjugation. Additionally, when the polymer to be conjugated is branched, there is a need for a specific modification of the synthetic peptide site to select only one free amine to be covalently coupled to the polymer, by avoiding several branches of the same molecule of the polymer that is conjugates (and cross-links) the same synthetic peptide molecule. More specifically, in the peptide derived from HIV gp41 containing more than one chemically reactive amine group ("free") which is available to be coupled to a polymer having reactive functionality (s) with amine, it is desirable chemically protecting one or more selected amine groups, leaving the free, deprotected amine groups available to covalently couple to the polymer. Additionally, it would be advantageous to provide a peptide derived from HIV gp41 which has the PEG coupled in a site-specific manner to one or more selected sites (i.e., at one or more selected amino acid positions) in the synthetic peptide. BRIEF DESCRIPTION OF THE INVENTION The present invention relates to a method for the specific chemical modification of the site of a peptide derived from HIV gp41 during the synthesis of the peptide, wherein the synthesized peptide has one or more amino acids having a chain amine lateral The method comprises incorporating into the peptide, or a fragment thereof, during synthesis, at least one amino acid selected to have its chain amine chemically bound by reaction with a chemical protective agent which protects the side chain amine from reactivity Subsequent chemistry with reactive functionality with amine; and at least one amino acid having an unprotected and free amine to react with an amine reactive functionality, wherein the free amine is selected from the group consisting of an N-terminal amine, a side chain amine, and a combination of the same. Also, a peptide derived from HIV gp41 having one or more amino acids containing a side chain amine is produced from this method, wherein at least one amino acid has its side chain amine chemically linked by reaction with a protective agent The chemical protects the sidechain amine from subsequent chemical reactivity with an amine-reactive functionality; and at least one amino acid of the synthetic peptide has an unprotected and free amine to react with an amine-reactive functionality, wherein the free amine is selected from the group consisting of an N-terminal amine, a side chain amine, and a combination of them. The present invention relates to a method for producing a substantially homogeneous conjugate composed of the peptide derived from HIV gp41 and the polymer, wherein the peptide derived from HIV gp41 has, incorporated in its amino acid sequence during the synthesis, one or more amino acids having a side chain amine which has been selected to be blocked by a chemical protective agent, leaving unblocked only the desired free amine (selected) of the synthetic peptide to be available for reaction with a polymer containing an amine-reactive functionality, by covalently coupling the synthetic peptide with the polymer only at the specific site (s) (the ) amino acid position (s) of the synthetic peptide) containing a free amine. The present invention also relates to a substantially homogeneous conjugate composed of the peptide derived from HIV gp41 and the polymer produced according to this method, according to the present invention. The present invention also provides a method for site-specific PEGylation of an HIV gp41 derivative peptide, wherein the PEG is covalently coupled in a site-specific manner to a peptide derived from HIV gp41. more particularly, the peptide derived from HIV gp41, which has been incorporated in its amino acid sequence at the amino acid positions selected during the synthesis, one or more amine groups (for example one or more of: an alpha amine or an epsilon amine (s)) which are blocked with a chemical protective agent of the chemical reactivity with the amine-reactive functionalities of the PEG during PEGylation, leaving therefore only the free amine group (s) available in the positions for PEGylation of selected amino acids (through chemical modification) of the synthetic peptide to be covalently coupled to the PEG. Using the method of the present invention, a substantially homogeneous composition comprising a peptide derived from PEGylated HIV gp41 containing one or more (as selected by carrying out the site-specific chemical modification method) conjugated amine groups is provided. PEG.

The methods of the present invention may further comprise removal of the chemical protective agent (in a "deprotection" step) by providing a substantially homogeneous conjugate composed of a peptide derived from HIV gp41 which is conjugated to a polymer only on site ( s) specific to the synthetic peptide, as selected in the embodiment of the method of the present invention (for example, through the use of chemical protection), wherein such conjugate retains substantial anti-HIV activity (when compares with the anti-HIV activity of the synthetic peptide when it is not conjugated to the polymer). The present invention also makes possible a method for treating HIV infections (preferably, HIV-1 infections) which comprises administering to an HIV infected individual a pharmaceutical composition comprising a substantially homogeneous conjugate composed of a synthetic peptide derived from HIV gp41 specifically site-coupled (eg conjugate) to the polymer. Preferably, the pharmaceutical composition is in an amount effective to inhibit transmission of HIV to the target cells, and / or in an amount effective to inhibit gp41-mediated fusion of HIV to target cells. A method for inhibiting the transmission of HIV to cells is also provided, which comprises contacting the virus in the presence of cells with the substantially homogeneous conjugate of the polymer and the synthetic peptide according to the present invention, in an amount effective to inhibit the infection of cells by HIV. Additionally, a method for inhibiting the transmission of HIV to cells is provided, which comprises adding to the virus and cells, a quantity of the substantially homogeneous conjugate of the polymer and the synthetic peptide according to the present invention, effective to inhibit the infection of the cells by HIV. A method for inhibiting HIV fusion (eg, a process by which HIV gp41 mediates fusion between the viral membrane and the cell membrane during HIV infection of target cells) is also provided., which comprises contacting the virus in the presence of the cells with a quantity of the substantially homogeneous conjugate of the polymer and the synthetic peptide according to the present invention, effective to inhibit HIV fusion. These methods can be used to treat individuals infected with HIV. The present invention also teaches the use of a substantially polymeric homogeneous conjugate and the synthetic peptide, produced by the method according to the present invention, in the manufacture of a medicament for use in the therapy of HIV infections (e.g. used in a method to inhibit HIV transmission, a method to inhibit HIV fusion, or a method to treat HIV infections), as described here. The medicament is preferably in the form of a pharmaceutical composition comprising a substantially homogeneous conjugate of polymer and the synthetic peptide according to the present invention, together with a pharmaceutically acceptable carrier. The above descriptions, features and advantages of the present invention will be apparent in the following Detailed Description of the Invention when read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a scheme of HIV-1 gp41 showing septete repeat region 1 (HR1) and septet repeat region (HR2) together with other functional regions of gp41. The exemplary sequences corresponding to HR1 and HR2, and the numbering of the amino acid positions are shown for purposes of illustration and in relation to the gplSO, strain HIVnIB. FIG. 2 shows a comparison of the sequences contained within the HRl region of gp41 of HIV-1 for purposes of illustration, and not limitation, as determined from several laboratory strains and clinical isolates, where some of the variations in the sequence of amino acids (for example, polymorphisms), as indicated by the one-letter code of the amino acid. FIG. 3 shows a comparison of the sequences contained within the HR2 region of gp41 of HIV-1 for purposes of illustration, and not limitation, as determined from several laboratory strains and clinical isolates, where some of the variations in the amino acid sequence (for example, polymorphisms), as indicated by the one-letter code of the amino acid. FIG. 4 is a scheme showing the synthesis of a peptide derived from HIV gp41 using a fragment condensation technique, wherein: the numerous represent the respective amino acid positions relative to the peptide derived from HIV gp41 synthesized; "K" represents a lysine internal to the sequence of the synthetic peptide, or to a fragment used in the synthesis of the synthetic peptide; "Ac" represents the acetylation of the N-terminus; and "NH" represents the amidation of the C-terminus. FIG. 5 is a scheme showing the synthesis of the peptide derived from modified HIV gp41, and a conjugate of the polymer and the synthetic peptide according to the present invention, wherein: the numbers represent the positions of the respective amino acids relative to the peptide of gp41 derivative of HIV synthesized; "K" represents a lysine internal to the sequence of the synthetic peptide, or to a fragment used in the synthesis of the synthetic peptide; "Ac" represents the acetylation of the N-terminus; "NH" represents the amidation of the C-terminus; "X" represents a chemical protective agent which is coupled to an amine epsilon of a selected amino acid by selectively blocking the amino acid side chain in the face of additional chemical reactivity; e "?" represents a polymer which has specificity for chemically coupling with a free amine group, and is conjugated to a free amine of an amino acid which is not coupled to a chemical protective agent in a specific chemical modification of the site. They produce: an isolated peptide derived from HIV gp41 having at least one amine group (ie, epsilon amine of the lysine residue at the position of amino acid 18) chemically protected by a chemical protective agent; and a substantially homogeneous conjugate composed of the peptide derived from HIV gp41 and the polymer, with a polymer conjugated to the peptide in a site-specific manner (for example, in the amine epsilon of the lysine residue at the position of amino acid 28). FIG. 6 is a scheme showing the synthesis of the modified peptide derived from HIV gp41, and a conjugate of the polymer and the synthetic peptide, according to the present invention, wherein the numbers represent the positions of the amino acids relative to the peptide derived gp41 of synthesized HIV; "K" represents a lysine internal to the sequence of the synthetic peptide, or to the fragment used in the synthesis of the synthetic peptide; "Ac" represents the acetylation of the N-terminus; "NH" represents the amidation of the C-terminus; "X" represents a chemical protective agent which is coupled to an amine epsilon by selectively blocking the side chain of the amino acid in the face of chemical reactivity; e "?" represents a polymer which is conjugated to an amine of an amino acid which is not coupled to a chemical protective agent in a specific chemical modification of the site. A gp41 HIV-derived peptide having at least one amine group (eg, the amine epsilon of the lysine residue at the position of amino acid 28) is produced chemically protected by a chemical protective agent; and a substantially homogeneous conjugate composed of the peptide derived from HIV gp41 and the polymer, with a polymer specifically conjugated to the site with the synthetic peptide (for example, in the amine epsilon of the lysine residue at the position of amino acid 18). DETAILED DESCRIPTION OF THE INVENTION Definitions The term "individual", when used herein for purposes of the specification and claims, means a mammal, and preferably a human. The term "target cells", when used herein for the purposes of the specification and the claims, means cells capable of being infected by HIV. Preferably the cells are human cells; and more preferably, human cells capable of being infected by HIV via a process that includes membrane fusion. The term "pharmaceutically acceptable carrier", when used for the purposes of the specification and claims, means a carrier medium that does not significantly alter the biological activity of the active ingredient (e.g., a polymer conjugate and the synthetic peptide in accordance with the present invention) to which it is added. A pharmaceutically acceptable carrier includes, but is not limited to one or more of water, buffered water, saline, 0.3% glycine, aqueous alcohols, isotonic aqueous solution; and may further include one or more substances such as glycerol, oils, salts such as sodium, potassium magnesium and ammonium, phosphonates, carbonate esters, fatty acids, saccharides (e.g., mannitol), polysaccharides, excipients, and preservatives and / or stabilizers (to increase storage life or when necessary and suitable for the manufacture and distribution of the composition). Preferably, the pharmaceutically acceptable carrier is suitable for intravenous, intramuscular, subcutaneous or parenteral administration. By the term "amino acid" for the purposes of the specification and the claims and with reference to the synthetic peptides used in the present invention, it is meant to refer to a molecule having at least one free amine group and at least one free carboxyl group . The amino acid may have more than one "free" amine group, or more than one free carboxyl group, or may further comprise one or more free chemically reactive groups that are not an amine or carboxyl group (eg, a hydroxyl, a sulfhydryl, etc.) The amino acid can be a naturally occurring amino acid (eg, L-amino acid), an amino acid that is not naturally occurring (eg, D-amino acid, a synthetic amino acid, a modified amino acid, an amino acid derivative, an amino acid precursor, and a conservative substitution.A person skilled in the art would know that the choice of amino acids incorporated into a peptide will depend in part on the specific physical, chemical or biological characteristics required for the antiviral peptide. part, by determining the structure and functions (for example, antiviral activity, as described in more detail here). For example, skilled artisans would know from the descriptions here that the amino acids in a synthetic peptide can be composed of one or more (L) -amino acids of natural formation and (D) -amino acids that are not naturally occurring. A preferred amino acid can be used for the exclusion of amino acids other than the preferred amino acid. A "conservative substitution", in relation to the amino acid sequence of a synthetic peptide used in the present invention, is a term used hereafter for the purposes of the specification and the claims to refer to the substitution of one or more amino acids in the sequence of the synthetic peptide in such a way that its biological activity remains substantially unchanged (for example, if before the substitution the peptide inhibits the gp41-mediated fusion of HIV at a concentration in the nanomolar range, after the substitution the inhibition of fusion mediated by HIV gp41 is observed even in the nanomolar range). As known in the art "conservative substitution" is defined by the aforementioned function, and includes amino acid substitutions that have substantially the same charge, size, hydrophilicity, and / or aromaticity as the replaced amino acid. Such substitutions are known to those of ordinary skill in the art to include, but are not limited to, glycine-alanine-valine; isoleucine-leucine; tryptophan-tyrosine; aspartic acid-glutamic acid; arginine-lysine; asparagine-glutamine; and serine-threonine. With particular relevance to the present invention, it is known in the art that a conservative substitution also includes the substitution of lysine with ornithine, by providing a free amine group (eg, epsilon amine). For peptides derived from HIV gp41, such substitutions may also comprise polymorphisms at the various amino acid positions throughout the relevant HR region (HR1 or HR2) of gp41 found in one or more plaques, laboratory strains, or HIV clinical isolates, which are available from public databases and are well known in the art (see also, for example, FIGS. 2 and 3, as illustrative examples). The term "polymer" when used herein for the purposes of the specification and claims, means a polymeric molecule which (a) is used in pharmaceutical applications to improve the pharmacological and / or biological properties when conjugated to a drug (and therefore, it is substantially non-toxic and substantially soluble in water); (b) has one or more functionalities per se, and / or after activation to become chemically reactive, can be used to covalently couple to a drug-free amine (eg, a synthetic peptide) by forming a conjugate of drug-polymer. With respect to the latter, the polymer preferably has an amine-reactive functionality to covalently couple to a synthetic peptide. A polymer can include, but is not limited to, polylysines or poly (D-L-alanine) -poly (L-lysine) s, or polyols. A preferred polyol comprises a water-soluble poly (alkylene oxide) polymer, and may have a straight or branched chain. The term "polyol" is preferably a water-soluble polyalcohol which may include, but is not limited to, polyethylene glycol ("PEG"), polypropylene glycol ("PPG"), diethylene glycol, triethylene glycol, ethylene glycol, dipropylene glycol, copolymers comprising PPG (eg, ethylene glycol / PPG), copolymers comprising PEG (eg, PEG / PPG), mPEG (monomethoxy-poly (ethylene) glycol) and the like. A polyol encompassing both homopolymers and copolymers, which may further have a structure comprising a branched structure or a linear structure as is known to those skilled in the art. Preferably, the polymer is substantially non-toxic when used for in vivo applications in individuals.

In a preferred embodiment, the polymer has a molecular weight in the range between about 200 dalton to about 40,000 dalton; and in a more preferred embodiment, the polymer has a molecular weight range between about 400 dalton to about 10,000 dalton. A preferred polymer for the application in the present invention comprises a polyethylene glycol ("PEG"), and a more preferred polymer for the application in the present invention comprises a polyethylene glycol having a molecular weight range, wherein the molecular weight range it is not less than about 400 dalton and is not greater than about 20,000 dalton. As previously described herein, there are several forms of PEG that typically differ in the terminal groups or chemically reactive functional groups to be used to covalently link the PEG molecule to a drug. Several PEGs are well known in the art. A preferred PEG, for use in coupling to one or more unprotected amine groups of the synthetic peptide according to the present invention, has a chemically reactive group (eg "a functionality") which can be used to covalently couple the PEG to one or more of the unprotected amine groups. The PEG may include but is not limited to, PEG-tresylate, heterobifunctional PEG, PEG dichlorotriazine, PEG succinimid carbonate, PEG benzotriazole carbonate, PEG-phenyl nitrophenyl carbonate, PEG trichlorophenyl carbonate, PEG carbonyl imidazole, succinimidyl succinate PEG, mPEG succinimidyl propionate, mPEG succinimidyl butanoate, PEG butyraldehyde, mPEG-propionaldehyde, PEG aldehyde, PEG-acetaldehyde, PEG acetaldehyde diethyl acetal, PEG carboxylic acid, mPEG phenyl ether succinimidyl carbonates, mPEG benzamide succinimidyl carbonates, thioester PEG, Linear PEG, branched PEG, and bifurcated PEG. A preferred polymer can be applied to the present invention for the exclusion of a polymer other than the preferred polymer. The terms "synthetic peptide" and "peptide derived from HIV gp41" are used synonymously here, in relation to a peptide employed in the present invention, and for the purposes of the specification and the claims, to refer to a peptide (a) comprising an amino acid sequence of not less than about 15 amino acids and not greater than about 60 residues of amino acids in length, and comprises at least a portion of the amino acid sequence (preferably, at least 90 contiguous amino acids) contained either in the HR1 region or in the HR2 region of HIV gp41 (more preferably HIV-1); Y (b) capable of inhibiting the transmission of Aviv to the target cells (preferably, by complexing with an HR region of gp41 of HIV-1 and inhibiting fusion between HIV-1 and the target cells), as can be determined by evaluation of the antiviral activity in vitro and / or in vivo, as will be described in more detail here. More preferably, the synthetic peptide employed in the present invention may comprise a sequence of no more than 28 amino acids and no more than about 51 amino acids in length, and even more preferably no more than about 36 amino acids and no more than about 51 amino acids in length . The term "isolated" when used with reference to a synthetic peptide means that it is substantially free of components that are not part of the integral structure of the peptide itself; for example, such as precursors substantially free of other chemicals when they are synthesized. They produce, or modify chemically using biological, biochemical, or chemical processes. The synthetic peptide may comprise, in its amino acid sequence, one or more conservative substitutions and / or one or more polymorphisms found in the sequence of the relevant region of HIV gp41, or may comprise one or more amino acid substitutions which are aggregated to stabilize the helicolidal structure and / or affect the oligomerization; provided that they substantially retain antiviral activity against HIV-1 (for example, an IC50 in the picomolar to micromolar range). The following are illustrative examples of peptides derived from HIV gp41 that can be site-specifically conjugated to the polymer according to the present invention. However, a preferred synthetic peptide can be used in the present invention for the exclusion of a synthetic peptide other than the preferred synthetic peptide. As is apparent to a person skilled in the art and from the teachings herein, a lysine in the amino acid sequence of a synthetic peptide can be substituted with another amino acid (naturally occurring or non-naturally occurring), which it has a side chain with a free amino group (eg, epsilon amine). Ornithine is an illustrative example of such an amino acid that can be used to replace a lysine. Preferably, to be used according to the present invention, for a synthetic peptide comprising the sequence derived from the HRl region of HIV gp41, the synthetic peptide comprises a contiguous sequence of at least 15 amino acid residues in the amino acid sequence of the SEQ ID NO: 1, or polymorphisms thereof, as the key determinants in this portion of the HRl region (eg, as indicated by the single-letter amino acid designation, NNLLRAIEQQHLLQLTVWG IKQLQARI LAVERYLKD, which represents the residues of amino acids 18 to 54 of SEQ ID NO: l) have been found to influence the structure and the biochemical and antiviral parameters described herein. Note that there are two lysine residues internal to this portion of the HR1 region, one or more of which may be used for site-specific coupling to a polymer according to the present invention. A preferred example of a synthetic peptide derived from the HR1 region of HIV gp41, and as it contains the amino acids found in the native sequence of this region, is illustrated by having an amino acid sequence of SEQ ID NO: 6. Other examples of a synthetic peptide derived from the HR-1 region of HIV gp41, and which contains the amino acids found in the native sequence of this region, are illustrated by having the amino acid sequence of SEQ ID NOs: 7-22, and can further comprising an amino acid sequence having at least 95% identity, and having more preferably at least 90% identity, with one or more of SEQ ID NOs: 6-22. More preferably to be used according to the present invention, a synthetic peptide derived from the HRl region of HIV gp41 contains one or more amino acid substitutions (eg, when compared to the amino acid sequence of SEQ ID NO: 1), which preferably allow the synthetic peptide to self-assemble in trimers (for example, a trimer which is composed of three molecules of the synthetic peptide), as described in more detail in the application, being processed together with the present, published as US. 20040076637. Examples of a synthetic peptide derived from the HR-1 region of HIV gp41 and which further comprises one or more amino acid substitutions which allow the synthetic peptide to self-assemble into trimers, are illustrated by having the amino acid sequences of SEQ ID NOs: 23-36, and may further comprise an amino acid sequence having at least 95% identity, and having more preferably at least 90% identity, with one or more of SEQ ID NOs: 23- 36 Note that such synthetic peptides have one or more lysine residues internal to this portion of the HR1 region, one or more of which may be chosen to be left unprotected (i.e., their reactive side chain group is not chosen to be coupled to the chemical protective agent); or they can be chosen to be chemically protected in the specific chemical modification of the site according to the present invention. Preferably for use in accordance with the present invention, for a synthetic peptide comprising the sequence derived from the HR2 region of HIV gp41, the synthetic peptide comprises a contiguous sequence of at least 43 to 51 amino acid residues of SEQ ID NO: 2 (for example, QQEKNEQEL), or polymorphisms thereof, since it has been discovered that the key determinants in this portion of the HR2 region influence the biochemical and antiviral parameters described herein. Note that there is an internal lysine residue in this sequence. Exemplary synthetic peptides derived from the HR2 region include, but are not limited to peptides having the amino acid sequences shown in SEQ ID NOs: 3, 4, 5, 37 to 63, and 175, and may comprise a sequence of amino acids having at least 95% identity, and more preferably having at least 90% identity, with one or more of SEQ ID NOs: 3, 4, 5, 37 to 63 and 175. Note that such synthetic peptides have one or more internal lysine residues (and / or in the case of SEQ ID NOs: 34, 39, 48, and 175, in the Terminal carboxy), one or more of which may be chosen to be left unprotected, or they can be chosen to be chemically protected, in the specific chemical modification of the site according to the present invention. More preferably for use in accordance with the present invention, a synthetic peptide derived from the HR2 region of HIV gp41 contains one or more amino acid substitutions (eg, when co-parenting with a relative portion of the amino acid sequence of SEQ ID NO. NO: 2), which preferably promote the helical happiness and / or stability of the synthetic peptide ("stabilized helix peptide") by imparting enhanced biological activity, as described in more detail in the application PCT / US04 / 42918, in progress next to the present. Examples of such stabilized helix peptides are illustrated by having the amino acid sequences of SEQ ID NOs: 64-92, and 113-174, and may further comprise an amino acid sequence having at least 95% identity, and it has more preferably at least 90% identity, with one or more of SEQ ID NOs: 64-92 and 113-174. Other examples of peptides chosen for their enhanced happiness and derivatives of the HR2 region of HIV gp41 may include SEQ ID NOs: 93-95. Note that such stabilized helix peptides have one or internal lysine residues (and in some cases more than 25% of the amino acid sequence of the synthetic peptide), one or more of which may be chosen to be left unprotected, or chosen to be chemically protected, in the specific chemical modification of the site according to the present invention. In another preferred embodiment according to the present invention, the synthetic peptide may comprise a "hybrid" peptide comprising the amino acid sequences derived from one or more of the fusion proteins of HIV-1, HIV-2 (see, for example , U.S. Patent No. 6,258,782). Examples of a hybrid synthetic peptide are illustrated by having the amino acid sequences of SEQ ID NOs: 96 to 112, and may further comprise an amino acid sequence having at least 95% identity, and having more preferably at least 90 % identity, with one or more of SEQ ID NOs: 96 to 112. Note that such illustrated examples of hybrid synthetic peptides have at least two internal lysine residues, one or more of which may be chosen to be left unprotected , or chosen to be chemically protected, in the chemical modification according to the present invention. The term "percent identity", when used herein for the purposes of the specification and the claims, with reference to a sequence used in accordance with the present invention, means that the sequence is compared ("Comparison Sequence") with a described sequence or reference ("Reference Sequence"), where a percent identity is determined according to the following formula: percent identity = [ l- (xC / yR) x 100] where xC is the number of differences between the Reference Sequence and the compared Sequence through the length of alignment between the Comparison Sequence and the Reference Sequence, where (a) each base or amino acid in the Reference Sequence that does not have a corresponding aligned base or amino acid compared to the compared Sequence, and (b) each gap in the Reference Sequence, and (c) each base or amino acid aligned in the Comparative Sequence that are different from a base or amino acid aligned in the Reference Sequence, makes a difference; e yR is the number of bases or amino acids in the Reference Sequence through the length of the Sequence compared to any gap created in the Reference Sequence as a result of alignment that is counted as a base or amino acid. Methods and programs for alignment between two predetermined sequences are well known in the art. Thus, for example, a Reference Sequence may be a synthetic peptide according to any of SEQ ID NOs: 1-175, and a Comparative Sequence is a peptide derived from HIV gp41 which is compared to the Reference Sequence, by determining an amino acid sequence having at least 85 identity with one or more of the amino acid sequences of SEQ ID NOs: 1-175. The term "chemical protective agent", when used herein for the purposes of the specification and the claims, means a chemical moiety that: (a) is chemically reactive with an amine of an amino acid, thereby blocking ("chemically protecting") the amine upon reaction with a polymer having a functionality that is reactive with amine; (b) can withstand (e.g., remains chemically bound by reaction with the amine to which it is chemically protecting) a step of deprotection known to those skilled in the art to remove tBU (t-butyl), Fmoc (9-) fluorenylmethoxycarbonyl), Boc (tert-butyloxycarbonyl) or trt (triphenylmethyl (triethyl)) of an amino acid; and (c) can be subsequently removed from the amine of the amino acid to which it is chemically bound by reaction, such that the amine is left unprotected and free for chemical reactivity with an amine-reactive functionality. More particularly, the chemical protective agent can withstand the removal of Fmoc or Boc from a peptide by reagents typically used in the art for such deprotection, including, for example, one or more of 20% piperidine, 2% DBU ( 1,8-diazabicyclo [5, 4, 0] undeca-7-ene), trifluoroacetic acid 50% to 90%, a quaternary amine (such as tetrabutyl ammonium fluoride), or an organic base such as potassium carbonate. For example, as described in more detail herein, the chemical protective agent can remain stable (bound by reaction with the amine group) until it is desired to remove the chemical protective agent, and then the chemical protective agent is removed in a deprotection step. Subsequent and separate (eg, using 2% hydrazine or other suitable reagent) to give a free amine. Such chemical protection agents are known in the art to include, but are not limited to, 1- (4,4-dimethyl-2,6-dioxocyclohexa-1-ylidene) ethyl ("Dde"), 1- (4, 4-dimethyl-2,6-dioxocyclohexa-1-ylidene) -3-methylbutyl (ivDde), allyloxycarbonyl (Alloc "), benzyloxycarbonyl (" Cbz "), and 2-chlorobenzyloxycarbonyl (" 2-C1-Z "). , in a synthetic peptide, the free amine group that reacts with the chemical protective agent is an N-terminal amine of an N-terminal amino acid, or an amine group of a side chain (e.g., epsilon amine) of an amino acid (if such an amino acid is the N-terminal amino acid, a C-terminal amino acid, or an internal amino acid), or a combination thereof, as determined by site-specific chemical modification, In a preferred embodiment, the agent chemical protector is stable to the amine bases to which the Fmoc, Boc, tBu, trt, or the like are unstable. "homogeneous", when used herein for the purposes of the specification and the claims and with reference to a conjugate composed of a peptide derived from HIV gp41 coupled with a polymer produced according to the present invention, means that at least 90%, and more preferably at least 95% of the resulting conjugate produced, contains the synthetic peptide specifically coupled from the site to the polymer as intended (i.e., as a single species) by an orthogonal protection strategy employed (as described in more detail in Example 5 here), according to the method of the present invention. The conjugate can be further purified using the separation technology that includes, but is not limited to, chromatographic techniques known in the art. The present invention provides a method for site-specific chemical modification of a peptide derived from HIV gp41, and provides a peptide derived from isolated HIV gp41 containing at least one chemically protected side chain amine, and containing at least one amine (for example N-terminal amino acid alpha amine, one or more side chain amines), or a combination thereof), deprotected and free for reactivity with an amine-reactive functionality. The peptide derived from isolated HIV gp41 can then be conjugated (covalently coupled) with a polymer at a site-specific location (i.e., at a particular amino acid position, on the synthetic peptide, having a free amine) which is select (not intentionally protecting it with a chemical protective agent) to be coupled to the polymer. Therefore, the coupling of the polymer to the synthetic peptide is via one or more of the free amine groups of the synthetic peptide, available for the chemical reaction with a polymer having a functionality which is reactive with amine. Accordingly, for example, a molecule or polymer is covalently coupled to an amino acid which is selected to have a free amine, to produce a substantially homogeneous conjugate composed of the polymer and the peptide derived from HIV gp41. For purposes of illustration, and without limitation, the following scheme demonstrates the methods according to the present invention, a peptide derived from HIV gp41 produced by a method according to the present invention, and a substantially homogeneous compound composed of synthetic peptide polymer. according to the present invention, using a peptide derived from HIV gp41 known as T20 (SEQ ID NO: 3). Scheme 1; the synthetic peptide, which is unmodified at the N-terminus after synthesis, has 3 free amine groups ("NH2") available for coupling to a polymer having an amine-reactive functional group; the alpha amine of the N-terminal amino acid, and two internal lysine residues designated Ki and K2 for ease of description), each with a side chain having an amine epsilon. Synthetic peptide: KINE E LELD K2WASLWNWF N iH2 N lH2.

Scheme 2: The synthetic peptide shown in scheme 1 is conjugated to a polymer ("?") Having an amine-reactive functionality to couple it to the synthetic peptide. A heterogeneous population of conjugates is possible from the conjugation process, as follows: Conjugates:?.? T $ L! HSUEESQNQQE KgWASWWF 2t ** YTSUHSLIEESQNQQE KINEQELLELD KgWASL N F I ? -YTSUHSUEESQNQQE? -YTSUHSL1EESQNGQE 2H. { TSUHSUEESQNQQ LWNWF I? TSLIHSL1EESQNQQE KTNEQELLELD K2WASLWN F NH2 NH2 Scheme 3: For purposes of illustration only, the free amine of the internal lysine residue "Kx" is selected to be free for chemical reactivity with an amine-reactive functionality. First, the synthetic peptide is synthesized to incorporate the amino acids, which have the desired amine groups to be blocked upon reactivity with the polymer, protected by a chemical protective agent ("X") to form an isolated gp41 HIV-derived peptide that has at least one amino acid with its chemically protected side chain amine (Scheme 3A); the polymer is then conjugated with such HIV-derived peptide gp41 (scheme 3B) in the only amino acid having a free amine (the lysine residue Ki); and the chemical protection agent is subsequently removed from the amino acids to which it was chemically bonded by reaction, to give a substantially homogeneous conjugate (3C scheme). Scheme 3A:? ^? TSLIHSLJEESQNQQEKiNEQELLELD K2WASLWNWF I I NH2 NH2X Scheme 3B: X ^ TTSLIHSLIEESQNQQE KiNEQELLELD K2WASLW F 1 I I NH2X It burns 3 C: KlNEQELLELD K2WASLWNWF I NH2 The following examples illustrate the present invention and should not be considered as limiting thereof. EXAMPLE 1 Synthetic peptides can typically be, and have been, synthesized by linear synthesis in a peptide synthesizer, using standard solid phase synthesis techniques and using Fmoc peptide chemistry and other standard peptide chemistries. Therefore, as shown in the synthesis of a fragment, illustrated herein, the synthesis in solid phase or other chemistry of standard peptides can be used to synthesize the synthetic peptide, wherein a chemically protected amino acid (for example an amino acid having its chemically protected side chain amine as described herein) can be added at the position of the desired amino acid at the point in the synthesis where such an amino acid is incorporated into the amino acid chain to produce the synthetic peptide (as illustrated in Example 6 from here) . However, in a preferred embodiment, the HIV gp41 derivative peptide undergoing experimentation is synthesized using a fragment condensation technique (see, for example, FIGS 4-6), as described in more detail in Example 5 of here. Briefly, 2 or more fragments are synthesized, each fragment containing the amino acid sequence found in a respective portion of the synthetic peptide. In the synthesis of a fragment, if desired, an amino acid having its free amine (for example the side chain amine) chemically protected by a chemical protection agent can be incorporated. The fragments are then assembled (covalently coupled in a manner and order) such that the synthetic peptide (with the appropriate amino acid sequence) is produced. T20 (SEQ ID NO: 3) was synthesized by the fragment condensation technique, as previously described in more detail (see, for example, U.S. Patent No. 6,015,881). Briefly, and as summarized in FIG. 4, first the fragments to be assembled in the synthetic peptide are synthesized. A fragment comprising the first 16 amino acids of SEQ ID NO: 2 was synthesized by standard solid phase synthesis (using a super acid sensitive resin), with acetylation ("Ac") of the N-terminus as long as had a hydroxyl group (-OH) at the C-terminus. A fragment comprising amino acids 17-26 of SEQ ID NO: 3 was synthesized, by standard solid phase synthesis with Fmoc at the N-terminus, and -OH at the C-terminus. A fragment comprising amino acids 27-35 of SEQ ID NO: 3 was synthesized by standard solid phase synthesis with Fmoc at the N-terminus and -OH at the C-terminus. As shown in FIG. 4, the fragment comprising amino acids 27-35 of SEQ ID NO: 3, was chemically coupled to amino acid 36 in the solution phase to result in a fragment comprising amino acids 27-36 with C-terminal amidation. The fragment of amino acids 17-26 of SEQ ID NO: 3 was coupled to the fragment of amino acids 27-36 of SEQ ID NO: 3 (after Fmoc removal of amino acid 27 of N-terminal). The resulting amino acid sequence having amino acids 17-36 of SEQ ID NO: 3, was chemically coupled to the fragment comprising amino acids 1-16 of SEQ ID NO: 3 (after removal of Fmoc from amino acid 17). of N-ter) to form a synthetic peptide comprising the amino acid sequence of SEQ ID NO: 3. The synthetic peptide was deprotected / subjected to decarboxylation (to remove the tBU, trt, and Boc used in the synthesis of each fragment) with a deprotection step, using a cocktail of trifluoroacetic acid / dithiotriethol / water (volume percent: 90/5/5) at 30 degrees C for 5 to 6 hours with shaking; and then purified using high resolution liquid chromatography, in inverted phase. The identity of the peptide was confirmed with electro-dew mass spectrometry. EXAMPLE 2 An embodiment of a method for site-specific chemical modification of the peptide derived from HIV gp41 is illustrated, which can be used to produce (a) a peptide derived from isolated HIV gp41 having a side chain amine group of one or more of its internal amino acids, chemically protected; and (b) a substantially homogeneous conjugate composed of the peptide derived from HIV gp41 and the polymer. More specifically, they are incorporated into a synthetic peptide (or a fragment thereof if the fragment assembly technique is used) during the synthesis: one or more amino acids having their side chain amine blocked by a chemical protection agent upon reactivity Subsequent chemistry with reactive functionality with amine; and one or more amino acids having an amine (for example selected from the group consisting of N-terminal alpha amine, one or more epsilon amines, and a combination thereof) deprotected, and free for reactivity with a reactive functionality with amine. An isolated synthetic peptide produced by this method for site-specific chemical modification can then be covalently coupled to the polymer to produce a substantially homogeneous conjugate by chemically reacting the unprotected (free) amine group (s) of the synthetic peptide. , with the reactive functionality with polymer amine. In this illustrative embodiment, T20 (SEQ ID NO: 3) was selected as the exemplary synthetic peptide, and the lysine residue at the position of amino acid 18 ("K18") (an amino acid with a side chain amine) was chosen to be chemically protected by a specific chemical modification of the site, leaving the lysine residue at the position of amino acid 28 ("K28") as the internal amino acid having a free amine. Subsequently the free amine can be chemically reacted with an amine-reactive functionality of a polymer, to covalently couple the polymer to the synthetic peptide via the lysine at the position of amino acid 28 of the amino acid sequence of the synthetic peptide. With reference to FIG. 5, T20 (SEQ ID NO: 3) was synthesized using the fragment condensation technique previously described in Example 1 here. Briefly, and as summarized in FIG. 5, a fragment comprising the first 16 amino acids of SEQ ID NO: 3 was synthesized by standard solid phase synthesis with the N-terminal amine of amino acid residue 1 ("Y") which is subjected to acetylation (" Ac "). A fragment comprising amino acids 17-26 of SEQ ID NO: 3 was synthesized by standard solid phase synthesis using Fmoc-Lys (ivDde) as amino acid residue 18, such that the chemical protection agent ivDde (" X "in FIG.5) blocks the epsilon amine group of K18 to subsequently react with an amine-reactive functionality. A fragment comprising amino acids 27-35 of SEQ ID NO: 3 was synthesized by standard solid phase synthesis, and chemically coupled to amino acid 36 in solution phase to form a fragment comprising amino acids 27-36 of the SEC ID NO: 3. The fragment comprising amino acids 17-26 of SEQ ID NO: 3 (with K18 protected with ivDde) was chemically coupled with the fragment of amino acids 27-36 of SEQ ID NO: 3 (which contains a lysine at position 28 ("K28") with a free amine epsilon). The resulting amino acid sequence comprising amino acids 17-36 of SEQ ID NO: 3 was combined with the fragment comprising amino acids 1-16 of SEQ ID NO: 3 to form an isolated HIV gp41 derived peptide having the amino acid sequence of SEQ ID NO: 3 and containing at least one amino acid having its chemically protected side chain amine group (blocked upon subsequent chemical reactivity with an amine reactive functionality) by a chemical protection agent. The synthetic peptide (SEQ ID NO: 3) was deprotected to remove the trt, Boc, and tBU protecting groups in the standard solid phase synthesis as described in more detail in Example 1, here (while K18 remains chemically protected ); undergoes decarboxylation; and then purified using inverted phase high resolution liquid chromatography. The gp41-derived HIV-isolated peptide was then used to couple a polymer in a site-specific manner to the K28 amine epsilon of SEQ ID NO: 3. To produce a substantially homogeneous conjugate composed of the gp41-derived peptide of HIV and the polymer, mPEG succinimidyl propionate ("mPEG-SPA") was chosen as the exemplifying polymer to conjugate it to T20 (SEQ ID NO: 3). T20 (SEQ ID NO: 3) with ivDde in the epsilon amine group of K18 (9.0 mg, 2.0 μmol) was dissolved in dimethyl formamide (DMF) (0.3 ml). Diisopropylethylamine was added (DIEA) (10 μl) to the reaction, and then mPEG-SPA was added (average molecular weight, 500 daltons ("5K"), 20 mg, 4.0 μmol) in DMF (1 ml). The mixture was stirred at room temperature and the reaction was monitored by HPLC until PEGylation was complete. To remove the ivDde chemical protection agent from the epsilon amine group of K18, hydrazine (40 μL) was added to the reaction to achieve 3% (v / v) hydrazine in the reaction mixture. Stirring was continued for another 30 minutes or until HPLC showed that the deprotection was complete. The reaction mixture was diluted with water (6.5 ml) to generate the final concentration of 20% DMF, and then filtered through a syringe filter (0.45 μm, 2 ml). Purification was carried out by HPLC on a polystyrene / divinylbenzene column (PRLP-S, 300A, 10 μm, 250 * 21.2mm) with acetonitrile-water-buffer 0.1% trifluoroacid as eluent. The collected fractions were evaluated by HPLC with detectors of both UV and ELS. The pure fractions are combined and subjected to lyophilization for two days. The desired conjugate, a substantially homogeneous conjugate composed of 5K-PEG-T20, was obtained as white fluffy solid (5.5 mg) after lyophilization.

In another variation of this embodiment, the alpha amine of the N-terminal amino acid of SEQ ID NO: 1 was not subjected to acetylation, but instead was protected with an Fmoc group. The synthesis process of the synthetic peptide and the conjugation to the polymer were carried out as contemplated in this Example 2. Therefore, the resulting substantially homogeneous conjugate comprises 5K-PEG-T20 in K28, except that the T20 (SEQ ID NO. : 3) of the conjugate contains a free alpha amine at the N-terminal amino acid (Y). EXAMPLE 3 Another embodiment of a method for the site-specific chemical modification of the peptide derived from HIV gp41 is illustrated, which can be used to produce (a) a peptide derived from HIV gp41 having one or more internal amino acids with a chemically protected side chain amine; and (b) a substantially homogeneous conjugate composed of the peptide derived from HIV gp41 and the polymer. In this illustrative embodiment, T20 (SEQ ID NO: 3) was selected as the exemplary synthetic peptide, and the lysine residue at amino acid position 28 ("K28") was chosen to be chemically protected by a specific chemical modification of the site, leaving the lysine residue at the position of amino acid 18 ("K18") as the internal amino acid that is free for subsequent coupling to the polymer via the side chain amine of lysine and an amine reactive functionality of a polymer. With reference to FIG. 6, T20 (SEQ ID NO: 3) was synthesized using the fragment condensation technique essentially as described in Example 1 here. Briefly, and as summarized in FIG. 6, a fragment of SEQ ID NO: 3 comprising the first 16 amino acids was synthesized by standard solid phase synthesis with the N-terminal amine of the amino acid residue 1 (Tyr) which was subjected to acetylation ("Ac"). A fragment of SEQ ID NO: 3 comprising amino acids 17-26 was synthesized by standard solid phase synthesis. A fragment of SEQ ID NO: 3 comprising amino acids 27-35 was synthesized by standard solid phase synthesis, using Fmoc-Lys- (ivDde) as amino acid residue 28 ("K28"), such that the chemical protection agent ivDde ("X" in FIG 6) blocks the epsilon amine group of K28 upon subsequent chemical reactivity with an amine-reactive functional group. The last fragment was coupled with amino acid 36 in the solution phase to form a fragment having amino acids 27-36 of SEQ ID NO: 3. The fragment having amino acids 17-26 (containing K18 with an amine epsilon) free) was combined with the fragment of amino acids 27-36 (with K26 protected by ivDde). The resulting amino acid sequence having amino acids 17-36 was combined with the fragment comprising amino acids 1-16 to form a synthetic peptide comprising the amino acid sequence of SEQ ID NO: 3. The synthetic peptide (SEQ ID NO. : 3) was deprotected to remove the protective groups trt, Boc, and TBu used in the standard solid phase synthesis as described in more detail in Example 1 here (while the K28 remains chemically protected); he underwent decarboxylation; and then purified using inverted phase high resolution liquid chromatography. The peptide derived from HIV-isolated gp41 was then used to couple it to a polymer in a site-specific manner with the K18 free amine epsilon of SEQ ID NO: 3. MPEG succinimidyl propionate ("mPEG-SPA") was chosen as the exemplary polymer to conjugate to T20 (SEQ ID NO: 3). T20 (SEQ ID NO: 3) with ivDde in the epsilon amine group of K28 (19.7 mg, 4.4 μmol) was dissolved in DMF (0.5 ml). DIEA (20 μL) was added to the reaction, and then mPEG-SPA (average molecular weight, 5000 dalton ("5K"), 50 mg, 10 μmol) in DMF (1 mL) was added. The mixture was stirred at room temperature and the reaction was monitored by HPLC until PEGylation was complete. To remove the ivDde chemical protection agent from the epsilon amine group of K28, hydrazine (45 μL) was added to the reaction to achieve 3% (v / v) hydrazine in the reaction mixture. Stirring is continued for another 30 minutes (or until HPLC shows that deprotection is complete). The reaction mixture was diluted with water (8.5 ml) to generate a final concentration of 20% DMF, then filtered through a syringe filter (0.45 μm, 2 ml). Purification was carried out by HPLC on a polystyrene / divinylbenzene column (PRLP-S, 300A, 10 μm, 250 * 21.2mm) with acetonitrile-water buffer 0.1% trifluoroacid as eluent. The collected fractions were evaluated by HPLC with detectors of both UV and ELS. The pure fractions were combined and subjected to lyophilization for two days. The desired conjugate, a substantially homogeneous conjugate composed of 5K-PEG-T20 in K18, was obtained as white fluffy solid (10.4 mg) after lyophilization. In another variation of this embodiment, the alpha amine of the N-terminal amino acid of SEQ ID NO: 1 was not subjected to acetylation, but was instead protected with an Fmoc group. The synthesis process of the synthetic peptide and the conjugation to a polymer were carried out as set forth in this Example 3. Therefore, the resulting conjugate comprises a substantially homogeneous conjugate composed of 5K-PEG-T20 in K18, except that the T20 (SEQ ID NO: 3) of the conjugate contained a free alpha amine at the N-terminal amino acid (Y). EXAMPLE 4 This example illustrates: (a) a method for determining the antiviral activity of the substantially homogeneous conjugates produced in accordance with the present invention; and (b) the need for a site-specific chemical modification in accordance with the present invention to produce a substantially homogeneous conjugate comprised of the polymer covalently coupled to the HIV gp41-derived peptide. When using an in vitro assay to demonstrate antiviral potency, it is important to note that the antiviral effect of the synthetic peptide, demonstrated in the in vitro assay, has been correlated with the antiviral effect of the synthetic peptide in vivo. In determining the antiviral activity (for example, one measure is the ability to inhibit transmission of HIV to target cells) of the peptide-polymer conjugates produced according to the present invention, an in vitro assay is used which has been demonstrated , by the data generated using the synthetic peptides derived from any of the HR regions of HIV gp41, which is predictive of the antiviral activity observed in vivo. More particularly, it has been shown that the antiviral activity observed using an in vitro infectivity assay ("Magi-CCR5 infectivity assay", see US Patent Nos. 6,258,782) correlates reasonably with the antiviral activity observed in vivo for the same peptides HIV gp41 derivatives. To emphasize this point further, it has been shown that T20 (SEQ ID NO: 3) and T1249 (SEQ ID NO: 96) each have potent antiviral activity against the HIV in both the in vitro infectivity assay and in human clinical tests. Infectivity assays record the reduction of infectious virus titer using the MAGI cell indicator lines or the CCR5 expression derivative cMAGI. Both cell lines exploit the ability of HIV-1 tat to transactivate the expression of a reporter gene of β-galactosidase stimulated by the HIV-LTR. The ß ~ gal reporter gene has been modified to localize in the nucleus and can be detected with the X-gal substrate as an intense nuclear stain within a few days of the infection. The number of stained nuclei can therefore be interpreted as equal to the number of infectious virions in the challenge inoculum before dyeing. Infected cells are enumerated using a CCD imaging device and the adapted primary and laboratory isolates show a linear relationship between virus entry and the number of infected cells visualized by the imaging device. In the MAGI and CMAGI trials, a 50% reduction in the infectious titer (Vn / Vo = 0.5) is significant, and provides the primary truncation value to evaluate the antiviral activity ("IC50" is defined as the dilution resulting in a 50% reduction in the title of the infectious virus). A secondary truncation of Vn / Vo = 0.1 corresponding to a reduction of 90% in the infectious titer ("IC90") is also evaluated. Substantially homogeneous conjugates evaluated for their viral activity were diluted in various concentrations, and evaluated in triplicate against an inoculum adjusted to give approximately 1500-2000 infected cells / well of a 48-well microtiter plate. The substantially homogeneous conjugate (in the respective dilution) was added to the cMAGI or MAGI cells, followed by the virus inoculum; and 24 hours later, an inhibitor of infection and cell-cell fusion (e.g., T20) was added to prevent secondary rounds of HIV infection and the virus from spreading cell by cell. The cells were cultured for a further 2 days, and then fixed and stained with the X-gal substrate to detect the HIV-infected cells. The number of infected cells was determined by each control and for the dilutions of substantially homogeneous conjugate, with the CCD imaging device, and then the IC 50 and the IC 90 (typically expressed in μg / ml) were calculated. In this example, several substantially homogeneous conjugates, produced separately by the methods described herein, were analyzed for their antiviral activity as shown in Table 1, and identified as follows. "Conjugate A" is a synthetic peptide having the amino acid sequence of SEQ ID NO: 3, which has a 2K PEG conjugated site-specifically to the N-terminal amine (therefore, the chain amines lateral of both K18 and K28 were chemically protected during synthesis). "Conjugate B" is a synthetic peptide having the amino acid sequence of SEQ ID NO: 3, which has a 2K PEG conjugate site-specifically to K18 (therefore, the N-terminal amine and the amine side chain K28 were chemically protected during synthesis). "Conjugate C" is a synthetic peptide having the amino acid sequence of SEQ ID NO: 3, which has a 2K PEG conjugate site-specifically to K28 (therefore, the N-terminal amine and the amine side chain of K18 were chemically protected during synthesis). "Conjugate D" is a synthetic peptide having the amino acid sequence of SEQ ID NO: 3 having a 5K PEG conjugated site-specifically to the N-terminal amine (therefore, the side chain amines) both K18 and K28 were chemically protected during the synthesis). "Conjugate E" is a synthetic peptide having the amino acid sequence of SEQ ID NO: 3 having a 5K PEG conjugated in a site-specific manner to K18 (thus the N-terminal amine and the chain amine K28 laterals were chemically protected during synthesis). "Conjugate F" is a synthetic peptide having the amino acid sequence of SEQ ID NO: 3, which has a 5K PEG conjugate site-specifically to K28 (therefore, the N-terminal amine and the amine side chain of K18 were chemically protected during synthesis). Table 1 From this comparison, it is clear that the antiviral activity of the synthetic peptide is best preserved when a polymer of the average size of 2K (2,000 dalton) is conjugated with the N-terminal amine versus K18 (with at least 5 times less activity) or K28 (with at least 10 times less activity). Similarly, it is clear that the antiviral activity of the synthetic peptide is best preserved when a 5K polymer is conjugated with the N-terminal amine versus K18 (approximately 5 times less activity) or K28 (approximately 7 times less activity). Furthermore, it can be concluded from this example, that the method of site-specific chemical modification according to the present invention, can be used to specifically couple the site of a polymer to an amino acid selected from the synthetic peptide to produce a substantially conjugate. homogeneous peptide-polymer conjugate having a desired level of biological activity (for example, in this example, the desired antiviral activity is measured by having an IC 50 less than 0.02 μg / ml) (for example, "Conjugate A of the Table 1) while avoiding to produce a peptide-polymer conjugate of several species lacking the desired level of biological activity using standard PEGylation (eg, a mixture of "Conjugate A" and "Conjugate B" and " Conjugate C "of Table 1) EXAMPLE 5 In this example, additional modalities of the method for the site specific chemical modification of a peptide derived from the e HIV gp41, wherein a synthetic peptide is incorporated during synthesis: one or more amino acids having its side chain amine blocked by a chemical protection agent upon subsequent reactivity with an amine-reactive functionality; and one or more amino acids having an amine (eg, selected from the group consisting of N-terminal alpha amine, one or more epsilon amines, and a combination thereof) deprotected and free for chemical reactivity with a reactive functionality with amine. The derivative of gp41 of The resulting isolated HIV is then conjugated with a polymer to produce a substantially homogeneous conjugate composed of polymer and the HIV gp41-derived peptide. Based on the teachings in Example 1 on a fragment condensation technique for synthesizing a peptide derived from HIV gp41, it is apparent to a person skilled in the art. technique that this fragment assembly technique can be used, and has been used for some perforation column of synthetic peptides having a sequence shown in SEQ ID NOs: 3-175, in the methods according to the present invention. Generally speaking, 3 fragments are typically synthesized (see, for example, FIG.3): an "N-terminal fragment" (usually composed of between 10 and 20 amino acids of the amino terminus of the synthetic peptide), a C-terminal fragment "(usually composed of between 10 and 20 amino acids of the carboxy terminal of the synthetic peptide), and a" middle fragment "(usually composed of between 10 and 20 of the amino acids found between the N-fragment) terminal and the c-terminal fragment, in the synthetic peptide), which are then assembled to produce the complete synthetic peptide, however, depending on the length, amino acid sequence, number and location of amino acids with amines side chain in the amino acid sequence of a particular synthetic peptide, anywhere from 2 to 4 fragments have been synthesized, and then assembled to complete the synthesis of that particular synthetic peptide For example, T1249 (SEQ ID NO: 96) was used in the site-specific chemical modification method according to the present invention. In this example, the synthetic peptide was synthesized by the fragment condensation technique using 3 fragments: an N-terminal fragment comprising amino acids 1-12 and containing a lysine at amino acid position 7 ("K7"), and an acetylated N-terminal amino acid; a medium fragment comprising amino acids 13 to 26 and containing a lysine at the position of amino acid 21 ("K21"); and a c-terminal fragment comprising amino acids 27 to 36 and containing a lysine at the position of amino acid 28 ("K28") and a lysine at the position of amino acid 31 ("K31") (the numbering of the positions of amino acids corresponding to the respective positions in SEQ ID NO: 96, ie, in the assembled synthetic peptide). A number of HIV gp41-derived peptides isolated according to the present invention were produced separately: (a) a synthetic peptide having the amino acid sequence of SEQ ID NO: 96, with a chemical protection agent in K7, K21, K28, and K31 (leaving only the free N-terminal amine for subsequent conjugation to the polymer); (b) a synthetic peptide having the amino acid sequence of SEQ ID NO: 96 with a chemical protection agent in the N-terminal amine, K21, K26, and K31 (leaving only the free-standing K7 amine chain for subsequent conjugation to the polymer), (c) a synthetic peptide having the amino acid sequence of SEQ ID NO: 96 with a chemical protection agent in the N-terminal amine, K7, K28, and K31 (leaving only the free K21 side chain amine for subsequent conjugation to the polymer); (d) a synthetic peptide having the amino acid sequence of sec 96 with a chemical protection agent in the N-terminal amine, K7, K21, and K31 (leaving only the free K28 side chain amine for conjugation Subsequent to the polymer, and (e) a synthetic peptide having the amino acid sequence of SEQ ID NO: 96 with a chemical protection agent in the N-terminal amine, K7, K21, and K28 (leaving only the amine of free K31 side chain for subsequent conjugation to the polymer.) Several substantially homogeneous conjugates were produced separately from these isolated HIV gp41 derived peptides having an amino acid sequence of SEQ ID NO: 96 and the method for modification specific chemistry described here, using different sizes of PEG, ranging from an average of 2K daltons ("2K") to an average of 20K daltons ("20K") Table 2 shows the antiviral activity of some of these conjugates substantially homogeneous identified as follows. "Conjugate A" is a synthetic peptide having the amino acid sequence of SEQ ID NO: 96 having a 2K PEG conjugated site-specifically to the N-terminal amine (therefore, side chain amines) of K7, K21, K28, and K31 were chemically protected during synthesis). "Conjugate B" is a synthetic peptide having the amino acid sequence of SEQ ID NO: 96, which has a 2K PEG conjugated in a site-specific manner to K7 (therefore, the N-terminal amine, and the side chain amines of K21, K28 and K31 were chemically protected during synthesis). "Conjugate C" is a synthetic peptide having the amino acid sequence of SEQ ID NO: 96 having a 2K PEG conjugated site-specifically to K21 (therefore, the N-terminal amine, and the amines side chain of K7, K28, and K31 were chemically protected during synthesis). "Conjugate D" is a synthetic peptide having the amino acid sequence of SEQ ID NO: 96, which has a 2K PEG conjugate site-specifically to K28 (thus the N-terminal amine, and the amines side chain of K7, K21, and K31 were chemically protected during synthesis). "Conjugate E" is a synthetic peptide having the amino acid sequence of SEQ ID NO: 96, which has a 2K PEG conjugated in a site-specific manner to K31 (therefore, the N-terminal amine, and the side chain amines of K7, K21, and K28) were chemically protected during synthesis). "Conjugate F" is a synthetic peptide having the amino acid sequence of SEQ ID NO: 96 having a 5K PEG conjugated site-specifically to the n-terminus amine. "Conjugate G" is a synthetic peptide having the amino acid sequence of SEQ ID NO: 96, which has a 5K PEG conjugated site-specifically to K7.

"Conjugate H" is a synthetic peptide having the amino acid sequence of SEQ ID NO: 96, which has a 5K PEG conjugated site-specifically to K21. "Conjugate I" is a synthetic peptide having the amino acid sequence of SEQ ID NO: 96 having a 5K PEG conjugated site-specifically to K28. "Conjugate J" is a synthetic peptide having the amino acid sequence of SEQ ID NO: 96 having a 5K PEG conjugated site-specifically to K31. Table 2 From this example and observing the results using a PEG of the average size of 2K (2000 daltons), it can be concluded that the site-specific chemical modification method according to the present invention can be used to specifically couple the site with a polymer to an amino acid selected from the synthetic peptide to produce a substantially homogeneous conjugate having a desired level of biological activity (for example, in this example, the desired antiviral activity is measured having an IC 50 less than 0.01 μg / ml) (for example, the "Conjugate A", "Conjugate B", and "Conjugate D" of Table 2) while avoiding producing a synthetic peptide-polymer conjugate of several species lacking such a desired level of biological activity, using PEGylation standard (for example, a mixture of the AE Conjugates of Table 2). EXAMPLE 6 In another example, a synthetic peptide having an amino acid sequence of SEQ ID NO: 174 was used in the site-specific chemical modification method according to the present invention. In this example, the synthetic peptide containing a lysine at the position of amino acid 30 ("K30") and a lysine at the position of amino acid 39 ("K39", the C-terminal amino acid, the numbering of the positions of the amino acids corresponding to the position in SEQ ID NO: 174), was synthesized by linear synthesis with a chemical protection agent in the N-terminal amine of the N-terminal amino acid, and in the side chain amine of K30 ( leaving only the free K39 side chain amine for subsequent conjugation to the polymer). Substantially homogeneous conjugates were separately produced from this peptide derived from isolated HIV gp41, using a polymer having an average size of 2K, a polymer having an average size of 5K, and a polymer having an average size of 20K For example, the synthetic peptide alone (not conjugated to a polymer) has a desired level of biological activity (for example, an antiviral activity is measured having an IC 50 less than or equal to 0.02 μg / ml), whereas a substantially conjugated homogeneous having a polymer with an average size of 2K had biological activity approximately equal to 0.02 μg / ml. Substantially homogeneous conjugates having a polymer of average size either 5K or 20K had a biological activity much higher than 0.1 μg / ml (ie, outside the range of biological activity for this example). EXAMPLE 7 The present invention provides substantially homogeneous conjugates composed of a peptide derived from HIV gp41 to which a polymer site-specific coupling ("synthetic peptide-polymer conjugates") is coupled. The antiviral activity of such synthetic peptide-polymer conjugates can be used in a method to inhibit the transmission of HIV to target cells, which comprises adding to the virus and cells an amount of synthetic peptide-polymer conjugate according to the invention, effective to inhibit the infection of cells by HIV, and more preferably, to inhibit HIV-mediated fusion between viruses and target cells. This method can be used to treat individuals infected with HIV (therapeutically) or to treat individuals newly exposed to, or at high risk of exposure (for example, through the use of drugs or high-risk sexual behavior) to HIV. (prophylactically) A) Yes, therefore, in the case of an individual infected with HIV-1, an effective amount of peptide-synthetic-polymer conjugate would be a sufficient dose (by itself and / or in conjunction with a dose regimen) to reduce the viral load of HIV in the individual to be treated. As is known to those skilled in the art, there are several standard methods for measuring HIV viral load, which include, but are not limited to, quantitative cultures of peripheral blood mononuclear cells and by plasma HIV RNA measurements. . The synthetic peptide-polymer conjugates of the invention can be administered in an individual administration, intermittently, periodically, or continuously, as can be determined by a physician, such as by monitoring the viral load. Depending on the formulation containing the synthetic peptide-polymer conjugate, and factors such as the polymer and synthetic peptide compositions used to form the synthetic peptide-polymer conjugate and whether they comprise a pharmaceutically acceptable carrier or not, and the nature of the pharmaceutically acceptable carrier, the synthetic peptide-polymer conjugate according to the present invention can be administered with a periodicity ranging from days to weeks or possibly longer. In addition, a synthetic peptide-polymer conjugate according to the present invention can be used, in antiviral therapy, when used in combination or in a therapeutic regimen (eg, when used simultaneously, or in a period with a drug). and period change with another) with other antiviral drugs used for the treatment of HIV (eg, including, but not limited to, other inhibitors of HIV entry (eg, CCR5 inhibitors, retocycline, and the like), HIV integrase inhibitors, reverse transcriptase inhibitors (eg, nucleosides or non-nucleosides), protease inhibitors, viral specific transcription inhibitors, viral processing inhibitors, HIV mutation inhibitors, inhibitors of the uridine phosphorylating enzyme , HIV vaccines, and the like, as is well known in the art.

For example, in a preferred embodiment, one or more antiviral agents can be combined in therapy with the synthetic peptide-polymer conjugate according to the present invention, thus increasing the effectiveness of the therapy, and reducing the ability of the virus to become resistant to antiviral drugs. Such combinations can be prepared from the effective amounts of antiviral agents (useful in the treatment of HIV infections) currently approved or approved in the future, which include, but are not limited to, abacavir, AZT, delaviridin, ddC , ddl, affaviranz, FTC, FTC (+) and (-), Raverset, GS 840, HBY097, 3TC, nevirapine, d4T FLT, emtricitabine, amprenivir, CGP-73547, CGP-61755, DMP-450, indinavir, nelfinavir, PNU-140690, ritonavir, saquinavir, telinavir, tenofovir, adefovir, atazanavir, iopinavir, VX 478, PRO-542, and betulin and dihydrobetulin derivatives (eg, PA-457). Effective dosages of these illustrative antiviral agents, which can be used in combinations with the peptide-synthetic polymer conjugate according to the present invention, are known in the art. Such combinations can include a number of antiviral agents that can be administered by one or more routes, sequentially or simultaneously, depending on the route of administration and the desired pharmacological effect, as is apparent to a person skilled in the art. Effective dosages of a synthetic peptide-polymer conjugate of the invention to be administered can be determined through methods well known to those skilled in the art; for example, determining potency, biological half-life, bioavailability, and toxicity. In a preferred embodiment, an effective dosage range of the synthetic peptide-polymer conjugate is determined by a person skilled in the art using data from routine in vitro and in vivo studies well known to those skilled in the art, by example, the in vitro effectiveness assays of the antiviral activity, as described herein, allow a person skilled in the art to determine the average inhibitory concentration (IC) of the synthetic peptide-polymer conjugate, necessary to block some amount of viral effectiveness (eg, 50% inhibition, IC5o, or 90% inhibition, IC90). The appropriate doses can then be selected by a person skilled in the art using the pharmacokinetic data of one or more standard animal models, such that a minimum plasma concentration (C (min)) of the synthetic peptide-polymer conjugate is obtained, which is equal to or exceeds a predetermined IC value. While the dosage varies typically depending on the chosen route of administration and dosage formulation, an exemplary dosage range of the synthetic peptide-polymer conjugate according to the present invention can vary from not less than 0.1 μg / kg of body weight and not more than 10 mg / kg of body weight; preferably a dosage range of from about 0.1-100 μg / mg of body weight, and more preferably, a dosage of from about 10 mg to about 250 mg of synthetic peptide-polymer conjugate. A synthetic peptide-polymer conjugate of the present invention can be administered to an individual by any means that allows the active agent to reach the target cells (cells that can be infected by HIV). Therefore, the synthetic peptide-polymer conjugates of this invention can be administered by any suitable technique, including oral, parenteral routes of administration (e.g., intramuscular, intraperitoneal, intravenous, or subcutaneous, intradermal, or implant injection or infusion) , nasal, pulmonary, vaginal, rectal, sublingual or topical, and can be formulated into appropriate dosage forms for each route of administration. The specific administration route will depend, for example, on the medical history of the individual, including any perceived or anticipated side effects of such administration, and the formulation of the conjugate to be administered (e.g., the nature of the polymer and the synthetic peptide of the which comprise the synthetic polymer peptide conjugate). More preferably, the administration is by injection (using, for example, intravenous or subcutaneous means), but could be by continuous infusion (using, for example, slow release devices or minipumps such as osmotic pumps, and the like). A synthetic peptide-polymer conjugate according to the present invention may further comprise a pharmaceutically acceptable carrier, and may further depend on the desired formulation, the site of administration, the method of administration, the route of administration, and other known factors. the doctors. The above description of the specific embodiments of the present invention have been described in detail for purposes of illustration, in view of the descriptions and illustrations, other persons skilled in the art can easily modify and adapt the present invention for various applications by applying current knowledge , without departing from the basic concept and therefore, such modifications and / or adaptations are considered to be within the meaning and scope of the appended claims.

Claims (34)

1. CLAIMS 1. A method for site-specific chemical modification of a peptide derived from HIV pg41 during peptide synthesis, wherein the peptide synthesized has one or more amino acids having a side chain amine, the method characterized in that it comprises incorporating in the peptide, or a fragment thereof, during synthesis: (a) at least one amino acid selected to have its side chain amine chemically bound by reaction with a chemical protection agent which protects the side chain amine upon reactivity Subsequent chemistry with reactive functionality with amine; and (b) at least one amino acid having an unprotected and free amine to react with an amine reactive functionality, wherein the free amine is selected from the group consisting of an N-terminal amine, a side chain amine, and a combination of them. The method according to claim 1, characterized in that the peptide derived from HIV gp41 is synthesized by covalently coupling two or more fragments to produce the synthesized peptide; and wherein is incorporated in at least one of the fragments, an amino acid having a side chain amine chemically linked by reaction with a chemical protection agent. 3. The method according to claim 1, characterized in that, the peptide derived from HIV gp41 is a peptide having an amino acid sequence of any of SEQ ID NOs: 1-175, or an amino acid sequence having at least 95 amino acids. % identity with one or more of SEQ ID NOs: 1-175. The method according to claim 1, characterized in that, the chemical protection agent is selected from the group consisting of 1- (4,4-dimethyl-2,6-dioxocyclohexa-1-ylidene) ethyl, 1- ( 4, 4-dimethyl-2,6-dioxocyclohexa-1-ylidene) -3-methylbutyl, allyloxycarbonyl, benzyloxycarbonyl and 2-chlorobenzyloxycarbonyl. The method according to any of claims 1, 2, 3, or 4, characterized in that, an amino acid having its side chain amine chemically linked by reaction with a chemical protection agent is lysine. The method according to any of claims 1, 2, 3, or 4, characterized in that, a side chain amine that is chemically bound by reaction with a chemical protection agent is an amine epsilon. 7. A peptide derived from isolated HIV gp41 having one or more amino acids containing a side chain amine, characterized in that at least one amino acid has its side chain amine chemically bound by reaction with a chemical protection agent which protects the side chain amine upon subsequent chemical reactivity with an amine-reactive functionality; and at least one amino acid of the peptide has an unprotected and free amine to react with an amine-reactive functionality, wherein the free amine is selected from the group consisting of an n-terminus amine, a side chain amine, and a combination from the same . 8. The peptide derived from HIV gp41 according to claim 7, characterized in that the peptide is a peptide having an amino acid sequence of any of SEQ ID NOs: 1-175, or an amino acid sequence having the minus 95% identity with one or more of SEQ ID NOs: 1-175. 9. The peptide derived from HIV gp41 according to claim 7, characterized in that the chemical protection agent is selected from the group consisting of 1- (4,4-dimethyl-2,6-dioxocyclohexa-l-ylidene) ethyl, 1- (4,4-dimethyl-2,6-dioxocyclohexa-l-ylidene) -3-methylbutyl, allyloxycarbonyl, benzyloxycarbonyl and 2-chlorobenzyloxycarbonyl. 10. The peptide derived from HIV gp41 according to any of claims 7, 8, or 9, characterized in that the amino acid having its side chain amine chemically bound by reaction with a chemical protection agent is lysine. The peptide derived from HIV gp41 according to any one of claims 7, 8, or 9, characterized in that, the side chain amine which is chemically bound by reaction with a chemical protection agent is an amine epsilon. 12. A method for producing a substantially homogeneous conjugate composed of the peptide derived from HIV gp41 and the polymer, the method, characterized in that it comprises: (a) synthesizing a peptide derived from HIV gp41 having one or more amino acids containing a side chain amine, such that at least one amino acid is selected to have its side chain amine chemically linked by reaction with a chemical protection agent which protects the side chain amine to the subsequent chemical reactivity with a reactive functionality with amine, and at least one amino acid of the peptide has an unprotected and free amine to react with an amine reactive functionality, wherein the free amine is selected from the group consisting of an N-terminal amine, a side chain amine, and a combination of them; and (b) covalently coupling a polymer to the peptide derived from HIV gp41 by chemically reacting an amine-reactive functionality of the polymer with a free amine group of the peptide derived from HIV gp41, wherein the polymer covalently couples only one or more amino acids having a free amine, and not at least one amino acid protected by the chemical protection agent, to produce the substantially homogeneous conjugate. The method according to claim 12, characterized in that the conjugate comprises a peptide derived from HIV gp41 covalently coupled to more than one polymer molecule, wherein each polymer molecule is coupled to an amino acid of the peptide derived from gp41 of HIV. The method according to claim 12, characterized in that the method further comprises removing the chemical protection agent from the substantially homogeneous conjugate. The method according to claim 12, characterized in that the peptide derived from HIV gp41 is synthesized by covalently coupling two or more fragments to produce the synthesized peptide; and wherein at least one of the fragments incorporates an amino acid having a side chain amine chemically linked by reaction with a chemical protection agent. 16. The method according to claim 12, characterized in that the peptide derived from HIV gp41 is a peptide having an amino acid sequence of any of SEQ ID NOs: 1-175, or an amino acid sequence having at least 95 amino acids. % identity with one or more of SEQ ID NOs: 1-175. 17. The method according to claim 12, characterized in that, the chemical protection agent is selected from the group consisting of 1- (4, 4- dimethyl-2,6-dioxocyclohexa-1-ylidene) ethyl, 1- (4,4-dimethyl-2,6-dioxocyclohexa-1-ylidene) -3-methylbutyl, allyloxycarbonyl, benzyloxycarbonyl and 2-chlorobenzyloxycarbonyl. 18. The method according to claim 12, characterized in that the polymer comprises polyethylene glycol. 19. The method according to any one of claims 12, 13, 14, 15, 16, 17 or 18, characterized in that, an amino acid having its side chain amine chemically bound by reaction with a chemical protection agent is lysine. The method according to any one of claims 12, 13, 14, 15, 16, 17 or 18, characterized in that the side chain amine that has been chemically bound by reaction with a chemical protection agent is an amine epsilon . 21. A substantially homogeneous peptide conjugate derived from HIV gp41 and polymer, produced according to the method of any of claims 12, 13, 14, 15, 16, 17 or 18. 22. The substantially homogeneous conjugate composed of peptide derived from HIV gp41 and polymer according to claim 21, characterized in that it further comprises a pharmaceutically acceptable carrier. -2. 3. The use of a substantially homogeneous conjugate composed of the peptide derived from HIV gp41 and the polymer according to claim 21 as an active therapeutic substance for the preparation of a medicament in the therapy of HIV infections. 24. The use of a substantially homogeneous conjugate composed of the peptide derived from HIV gp41 and the polymer according to claim 22 as an active therapeutic substance for the preparation of a medicament in the therapy of HIV infections. 25. The use of a substantially homogeneous conjugate composed of the peptide derived from HIV gp41 and the polymer according to any of claims 23 or 24, characterized in that, the substantially homogeneous conjugate is used as part of a therapeutic regimen containing one or more additional antiviral agents for the preparation of a medicament for the therapy of HIV infections. 26. The use of a substantially homogeneous conjugate composed of the peptide derived from HIV gp41 and the polymer according to claim 21, for the preparation of a medicament for a therapeutic application comprising the treatment of HIV. A pharmaceutical composition, characterized in that it comprises a substantially homogeneous conjugate composed of the HIV gp41-derived peptide and the polymer according to claim 21. 28. A pharmaceutical composition, characterized in that it is composed of a substantially homogeneous peptide conjugate. gp41 derivative of HIV and the polymer according to claim 22. 29. The use of an effective amount of the substantially homogeneous conjugate composed of the HIV gp41-derived peptide and the polymer according to claim 21, for the preparation of a medication for the inhibition of HIV transmission to cells. 30. The use of an effective amount of a pharmaceutical composition according to claim 27, for the preparation of a medicament for inhibiting the transmission of HIV to cells. 31. The use according to claim 29, characterized in that, the substantially homogeneous conjugate is added as a component of a therapeutic regimen. 32. The use according to claim 30, characterized in that the pharmaceutical composition is added as a component of a therapeutic regimen. 33. The use of the substantially homogeneous conjugate composed of peptide derived from HIV gp41 and polymer according to claim 21, for the preparation of a medicament for inhibiting fusion of HIV. 34. The use of a pharmaceutical composition according to claim 27, for the preparation of a medicament for inhibiting HIV fusion.