Polymers containing enzymatically degradable bonds, 1. Chymotrypsin catalyzed hydrolysis of p‐nitroanilides of phenylalanine and tyrosine attached to side‐chains of copolymers of N‐(2‐hydroxypropyl)methacrylamide

Abstract A series of copolymers of N ‐(2‐hydroxypropyl)methacrylamide were prepared, which contained side chains of the general formula ‐Gly‐X‐Y‐NAp, where Gly ¨ glycine; X ¨ glycine, alanine, β‐alanine, valine, leucine, isoleucine, phenylalanine; Y ¨ phenylalanine or tyrosine; NAp ¨ p ‐nitroanilide, the latter modelling biologically active compounds. The rates of chymotrypsin‐catalyzed hydrolysis of p ‐nitroanilide groups at pH = 8,0 and 25°C were determined over a range of substrate concentrations to derive values for k cat and K M . The results allowed us to determine the influence of the structure of side chains on the rate of cleavage of Y‐NAp. The increase in the susceptibility to chymotrypsin attack with an increasing spacing of the Y‐NAp residue from the backbone of the polymer chains is demonstrated by comparing the kinetic data of copolymers containing ‐Gly‐Gly‐Phe‐Phe‐NAp, ‐Gly‐Gly‐Phe‐NAp and ‐Gly‐Phe‐NAp side chains. Results obtained with α‐chymotrypsin were compared with the cleavage of the above polymer substrates with chymotrypsin covalently bound to a copolymer of N ‐(2‐hydroxypropyl)methacrylamide.