Patent ID: 7129327

Claim:
A method of producing a composition containing modified protein or polypeptide molecules, or salts thereof, wherein said modified protein or polypeptide molecules of said composition consist essentially of a compound selected from A-X-Z-X′—B wherein A is a residue of a protein or polypeptide having a carboxy and amino terminus and is connected to X-Z-X′—B exclusively at said carboxy or amino terminus; B is a polymeric compound; X and X′ independently from each other are bivalent organic radicals or independently from each other are present or absent; Z is a bivalent radical selected from the group consisting of: —C(R)═N—, —N═C(R)—, —CH(R)—NH—, —NH—CH(R)—, —C(R)═N—Y—NC(R)—, —N═C(R)—Y—C(R)N—, —CH(R)—NH—Y—NH—CH(R)— and —NH—CH(R)—Y—CH(R)—NH—, —C(R)═N—O—, —O—N═C(R)—, —CH(R)—NH—O—, —O—NH—CH(R)—, —C(R)═N—O—Y—O—N═C(R)—, —O—N═C(R)—Y—C(R)═N—O—, —CH(R)—NH—O—Y—O—NH—CH(R)— and —O—NH—CH(R)—Y—CH(R)—NH—O—; where R is hydrogen or an aliphatic, cycloaliphatic, aromatic or araliphatic hydrocarbon group; and Y is a bivalent organic group, wherein said method comprises condensing a compound of the formula: A-X—R 1 wherein R 1 is a —CO—R group, an acetalized formyl group, or an amino or protected amino group, and A,R, and X are as defined above, with a compound of formula: R 2 —X′—B or a compound of formula: R 2 —Y—R 2 where R 2 is amino when R 1 is —CO—R or acetalized formyl and R2 is —CO—R or acetalized formyl when R 1 is amino, and X′, Y, R and B are as defined above, to form a Schiff base, hydrazone, oxime or azomethine compound, and optionally, reducing the —C(R)═N— or —N═C(R) formed by the condensation to CH(R)—NH— or NH—CH(R)—, respectively, and optionally forming a salt.