Enzymatic splitting of side chains in soluble polymers. The effect of length and structure of the side chain

Abstract

AbstractA series of soluble polymers was prepared by copolymerization of the 4‐nitrophenol ester of N‐methacryloylated ω‐amino acids (1a – i), of N‐methacryloyldiglycine (2b), of 6‐(N‐methacryloylglycylamino)‐ and of 6‐(N‐methacryloylglycylglycylamino)hexanoic acid (3a and 3b) with N‐(2‐hydroxypropyl)methacrylamide (HPMA). The resulting polymers contained roughly 3 mol‐% of nitrophenol groups. Polymeranalogous reaction with 4′‐nitro L‐phenylalanineanilide (4a) or with its N‐glycyl and N‐glycylglycyl derivates (4b and 4c), yielded polymers which at the end of their side chain of various length and structure had a bond degradable with chymotrypsin. The rate of enzymatic hydrolysis was investigated as a function of the length and structure of side chain. It was found that in copolymers possessing side chains formed by ω‐amino acid residues, the rate of hydrolysis increases with increasing length of the side chain. The rate of cleavage of the peptide bond has a maximum value for a spacer that possesses six methylene groups. With increasing length of the side chain the rate of hydrolysis again decreases. A similar dependence was observed for side chains formed by dipeptides of ω‐amino acids and glycine. In copolymers with oligoglycine side chains, the rate of enzymatic hydrolysis also increases with increasing length of side chain. In other types of side chains formed by combination of hydrophobic and hydrophilic segments, a number of factors become operative which affect the rate of enzymatic hydrolysis and are very difficult to specify.