Abstract: Graft polymers with reactive groups for linking to peptides for use in tissue engineering and to drugs to provide drug delivery systems and useful per se to release amino acids and useful, for example, for wound closure devices, pins, screws, anastomosis rings, and surgical implants, consist essentially of biodegradable homopolymer or copolymer backbone joined at carbon alpha to carbon of backbone carbonyl group, to side chain amino acid pendant group at a carbonyl moiety of said pendant group wherein said side chain contains reactive amino acid group. The graft polymers are prepared by reacting amino acid halide having other reactive groups protected, with biodegradable polymer containing carbanion on carbon alpha to carbon of carbonyl group, and then deprotecting the protected groups. Biodegradable polymer containing carbanion on carbon alpha to carbon of carbonyl group, for use in preparing the graft polymers herein or for otherwise reacting, e.g.