REVERSIBLE LIGHT-STIMULATED ACTIVATION AND DEACTIVATION OF ALPHA-CHYMOTRYPSIN BY ITS IMMOBILIZATION IN PHOTOISOMERIZABLE COPOLYMERS

The enzyme alpha-chymotrypsin was immobilized in acrylamide copolymers which contain photoisomerizable components. The resulting enzyme-copo lymer assemblies reveal photoswitchable ''on-off'' biocatalytic activi ties. Three kinds of acrylamide copolymers cross-linked with 4-(methac ryloylamino)azobenzene (polymer 1) rospiro[indoline-2,2'-[2H-1]benzopy ran](polymer2), and bis[4-(dimethylamino)phenyl](4-vinylphenyl)methyl leucohydroxide (polymer 3) were used to immobilize the enzyme. The enz yme reveals bioactivity (position ''on'') in the copolymer isomer stat es 1b, 2b, and 3b, respectively, while its activity is blocked (positi on ''off'') in copolymers 1a, 2a, and 3a, respectively. The activity o f the enzyme is assayed toward the hydrolysis of N-(3-carboxypropionyl )-L-phenylalanine p-nitroanilide (7). The photostimulated activities o f the enzyme entrapped in the different copolymers correlate with the permeability properties of the substrate 7 across the photoisomer form s of the copolymers. While the copolymer isomer forms 1a, 2a, and 3a e xhibit poor permeability toward the substrate 7, the copolymers 1b, 2b , and 3b are permeable toward the substrate 7.