STRUCTURE-TO-FUNCTION RELATIONSHIPS IN THE BIODEGRADATION OF POLY(AMINO ACID)S

Synthetic poly(amino acid)s are polymers with a polypeptide backbone. A rational synthesis of poly(amino acid)s makes it possible to design polymer materials with the required pattern of enzymatic biodegradatio n. Structural variations controlling the biodegradability of poly(amin o acid)s can be produced either by copolymerization or via polymer mod ification reactions. The biodegradation of poly[N-5-(2-hydroxyethyl)-L -glutamine] (PHEG) and related copolymers by endopeptidases and exopep tidases was studied. The degradation of PHEG, as a homopolymer, by the endopeptidase mechanism (papain) was found to be a nonrandom process, due to the multiple attack of enzyme on the same polymer coil. The en zyme-specific structures in copolymers can strongly influence the degr adation rate by specific enzymes. A concerted action of endopeptidases and exopeptidases is needed to ensure the degradation of PHEG and rel ated copolymers down to monomer units. (C) 1998 Elsevier Science Limit ed. All rights reserved.