Biopolymers and cell. 1997; 13 (3): 213 - 217

An activity of a-chymotrypsin immobilized by bilayer phospholipid membranes

Yu. E. Shapiro, A. V. Smirnova, 1. F. Makarevich, A. V. Ulesov

The kinetic parameters for enzymatic hydrolysis of classic substrate, p-nitrophenyl acetate, in presence of a-chymotrypsin immobilized and nonimmobilized by phospholipid bilayer liposomes are essentially different. The immobilization of a-chymotrypsin tends to increase of the value of Michaelis constant and to decrease of the value of maximum, rate by a factor of 2.3. These distinctions are conditioned by diffusional factors arised with immobilization of enzyme. Indeed, the value of appropriate Michaelis constant calculated according to the diffusion coefficient for components of reaction medium is practically in agreement with experimental constant for a-chymotrypsin immobilized by phospholipid vesicles.