Polymers containing enzymatically degradable bonds, 3. Poly[N‐(2‐hydroxypropyl)methacrylamide] chains connected by oligopeptide sequences cleavable by trypsin

Copolymers (12–20) of N‐(2‐hydroxypropyl)methacrylamide (1) with p‐nitrophenyl esters of N‐methacryloylated oligopeptides (2–10) were prepared. These copolymers were crosslinked below the gel‐point with N,N′‐bis(Nε‐Boc‐lysine)hexamethylenediamine (11). The crosslinks connecting poly[N‐(2‐hydroxypropyl)methacrylamide] chains contained an oligopeptide sequence of 2–4 amino acids: ‐Gly‐Nε‐Boc‐Lys‐; ‐Gly‐X‐Nε‐Boc‐Lys‐ (X…Gly, Val, Leu, Phe, D‐Phe); ‐Ala‐Gly‐Val‐Nε‐Boc‐Lys; ‐Gly‐Gly‐Y‐Nε‐Boc‐Lys‐(Y…Phe, Val). After removal of the Boc blockade of lysine, copolymers degradable by trypsin were obtained. Changes in the molecular weight distribution of the polymers studied after incubation with trypsin allowed us to evaluate the influence of steric effects and of subsite interactions on the degradability of polymeric substrates.