Polymer-modified synthetic proteins

A composition comprising a synthetic bioactive protein comprising a polypeptide chain comprising an amino acid sequence of a ribosomally specified glycoprotein, said polypeptide chain having one or more water-soluble polymers attached thereto and a monomer polypeptide molecular weight of greater than 25 kDa, wherein the composition is uniform with regard to the amino acid attachment sites of the polymer, and wherein the polymer is attached to at least one internal amino acid of the protein.

A composition comprising a synthetic bioactive protein comprising a polypeptide chain comprising an amino acid sequence of a ribosomally specified glycoprotein, said polypeptide chain having one or more water-soluble polymers attached thereto, wherein said polypeptide chain together with said attached one or more water-soluble polymers has a molecular weight greater than 25 kDa, wherein the composition is uniform with regard to the amino acid attachment sites of the polymer, and wherein the polymer is attached to at least one internal amino acid of the protein, and wherein said synthetic bioactive protein possesses a bioactivity that mimics a bioactivity associated with a cytokine selected from the group consisting of an erythropoiesis stimulating protein, Rantes, and granulocyte colony stimulating factor.

A method of treating a human disease or condition that comprises administering to an individual in need of such treatment an effective amount of a pharmaceutical composition comprising a polymer-modified bioactive protein having a monomer polypeptide molecular weight greater than about 25 kDa, wherein the polymer-modified bioactive protein possesses a bioactivity that mimics a bioactivity associated with a natural human protein receptor or fragment thereof, protein receptor ligand or fragment thereof, or a cytokine, wherein the composition is uniform with regard to the attachment sites of the polymer to the protein, and wherein the polymer is attached to at least one internal amino acid of the protein.

A method of producing a polymer-modified polypeptide chain of a synthetic bioactive polymer-modified protein, said method comprising

• providing peptide segments comprising non-overlapping amino acid sequences of a polypeptide chain of said synthetic bioactive polymer-modified protein, wherein one or more of said peptide segments comprises an irregular amino acid having a first chemoselective functional group attached thereto, and
• reacting said irregular amino acid with a water-soluble polymer having a second chemoselective functional group attached thereto, wherein the second chemoselective group is uniquely and mutually reactive with the first chemoselective group, to obtain at least one of said peptide segments having a polymer attached thereto,
• chemically ligating said peptide segments to obtain a polymer-modified polypeptide chain of said synthetic bioactive polymer-modified protein.

A method of producing a polymer-modified polypeptide chain of a synthetic bioactive polymer-modified protein, said method comprising:

• a. chemically ligating peptide segments comprising non-overlapping amino acid sequences of said synthetic bioactive polymer-modified protein to form a full length polypeptide chain corresponding to the amino acid sequence of said synthetic bioactive polymer-modified protein, wherein one or more of said peptide segments comprises an irregular amino acid having a first unique chemoselective group attached thereto;
• and
• b. chemically ligating a water-soluble polymer to said full length polypeptide chain, said water-soluble polymer comprising a second chemoselective group that is mutually and uniquely reactive with said first unique chemoselective group, whereby a polymer-modified polypeptide chain of said synthetic bioactive polymer-modified protein is produced.