Patent ID: 7538182

Claim:
A composition containing conjugated derivatized protein or polypeptide molecules, or salts thereof, wherein said conjugated derivatized protein or polypeptide molecules of said composition consist essentially of a compound selected from formula: A-X-Z-X′—B wherein A is a carboxy- or N-terminal amino acid residue of the protein or polypeptide; X and X′ are independently 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)—, —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—, wherein R is hydrogen or an aliphatic, cycloaliphatic, aromatic or araliphatic hydrocarbon group and Y is a bivalent organic group; and B is a cytotoxic agent; wherein said conjugated derivatized protein or polypeptide molecules, or salts thereof, are produced via formation of a Schiff base, hydrazone, oxime or azonethine compound that results in the presence of at least one radical having the formula —C(R)═N—, or —N═C(R)—, or, when reduced, —CH(R)—NH— or —NH—CH(R)—.