Effects of guest proteins on hydrolysis of aryl esters in reversed micellar systems

• Published in: Nippon Nōgeikagaku Kaishi Vol. 69; no. 3; pp. 331 - 336
• Main Authors: Hirai, K.R. (Gunma Univ., Kiryu (Japan). Coll. of Technology), Enomoto, A, Nakamura, K
• Format: Journal Article
• Language: Japanese
• Published: Tokyo Japan Society for Bioscience, Biotechnology, and Agrochemistry 01.03.1995; Nippon Nōgei Kagakukai
• Subjects: CHYMOTRYPSINE; EMULSION; ESTER; ESTERES; HIDROLISIS; HYDROLYSE; PROTEINAS; PROTEINE; QUIMOTRIPSINA
• ISSN: 0002-1407; 1883-6844
• DOI: 10.1271/nogeikagaku1924.69.331

The catalytic hydrolysis rates of p-nitrophenyl acetate and p-nitrophenyl octanoate in water-in-oil microemulsions of Aerosol-OT (AOT; sodium bis(2-ethylhexyl) sulfosuccinate) in isooctane were studied. Bovine pancreas alpha-chymotrypsin, bovine serum albumin (BSA), and palmitic acid-BSA were used as catalysis. The rates of alpha-chymotrypsin-catalyzed hydrolysis of p-nitrophenyl acetate and p-nitrophenyl octanoate had a bell-shaped pattern of dependence on omega0 (=[H2O]/[AOT]) with maximal at omega0=12. In the palmitic acid-BSA-catalyzed reaction, the omega0-profiles of rate constants for the two esters were similar to those of alpha-chymotrypsin-catalyzed hydrolysis, but had with maxima at omega0=15. Comparison of the catalytic activity of alpha-chymotrypsin with that of palmitic acid-BSA in the microemulsions showed that the water pool radius that gave the highest catalytic activity was almost the same as that of the protein. The omega0-profile of the rate constant for BSA-catalyzed hydrolysis of p-nitrophenyl acetate was a broad bell-shape. The radius of the water pool that gave the maximum activity near omega0=20 was larger than that of BSA. The results show that omega0-dependence of the catalytic activity of solubilized protein is affected by the surface characteristics of the protein