Enzymatic hydrolysis of random copolypeptides consisting of N-hydroxyethyl-L-glutamine and L-alanine, L-leucine, or L-valine

Two component water soluble random copolypeptides consisting of N-hydroxyethyl-L-glutamine and hydrophobic L-amino acid, such as L-alanine, L-leucine, or L-valine, were prepared by carrying out aminolysis reactions with 2-amino-pi-ethanol (E) on starting copolymers consisting of gamma-benzyl-L-glutamate (B) and the corresponding hydrophobic L-amino acid. The effects on copolymer composition and sequential distributions, as well as molecular conformations, on the rate of degradation by ficin in a pseudoextracellular fluid (PECF) at pH 7.4 and 37.0 degrees C were investigated to simulate in vivo polymer degradation. All the samples were found to be extensively degraded by random chain fracture with ficin. Further, the degradation data for these samples followed the Michaelis-Menten rate law, being of the first order in ficin concentration. The nature of the side chains and the molecular conformations are important to the rate of degradation by ficin in vitro. (C) 1999 Elsevier Science Ltd. All rights reserved.