Polymers containing enzymatically degradable bonds, 2. Poly[N-(2-hydroxypropyl)methacrylamide] chains connected by oligopeptide sequences cleavable by chymotrypsin

Copolymers of N-(2-hydroxypropyl)methacrylamide ( 1 ) with p-nitrophenyl esters of N-methacryloylated oligopeptides ( 2–16 ) were prepared. These copolymers were crosslinked below the gel point by diamines ( 17–27 ). The crosslinks connecting poly[N-(2-hydroxypropyl)methacrylamide] chains contained an oligopeptidic sequence of 2–4 amino acids, cleavable by α-chymotrypsin: -Gly-X-Y- (X… Gly, Ala, β-Ala, Val, Leu, Ile, Phe, D -Phe; Y… Phe, Tyr), -Gly-Gly-Phe-Y-; -U-Gly-Val-Phe- (U… Ala, Gly); -Gly-Phe-W- (W… Ala, Gly, D -Phe); -Gly-Phe-Ala-U-. The changes in the distribution of molecular weights of the studied copolymers, after incubation with α-chymotrypsin, allowed us to estimate the amount of degradable crosslinks and to determine the relationship between the structure and cleavability. The results are interpreted from the viewpoint of the contribution of subsite (S-P) interactions to the degradability of the studied polymers.