title: Pressure effects on enzyme reactions in mainly organic media: alpha-chymotrypsin in reversed micelles of Aerosol OT in octane.
abstract: Biocatalytic transformations in reversed micelles formed by anionic surfactant Aerosol OT in octane have been studied at high pressures by an example of alpha-chymotrypsin-catalyzed hydrolysis of N-carbobenzoxy-L-tyrosine p-nitrophenyl ester and N-succinyl-L-phenylalanine p-nitroanilide. For the first time it has been found that the enzyme retains high activity in these water-in-oil microemulsions up to a pressure of 2 kbar. The value of the activation volume (delta V*) for the enzyme reactions shows a dependence on the water content in the system. When the size of the micellar aqueous inner cavity (as evaluated at 1 atm) approaches the molecular size of alpha-chymotrypsin, delta V* becomes significantly different from the value in aqueous solution and in the micelles with a larger size. Possibilities of regulating the enzyme activity by pressure in systems with a low content of water are discussed.
authors.affiliation: INSERM U 128, Montpellier, France.
authors.forename: V V
authors.initials: VV
authors.lastname: Mozhaev
authors.forename: N
authors.initials: N
authors.lastname: Bec
authors.forename: C
authors.initials: C
authors.lastname: Balny
mesh_terms: D000818:Animals; D002384:Catalysis; D002417:Cattle; D002918:Chymotrypsin / Q000378:metabolism*; D004143:Dioctyl Sulfosuccinic Acid / Q000737:chemistry*; D006868:Hydrolysis; D008823:Micelles; D009795:Octanes / Q000737:chemistry*; D010179:Pancreas / Q000201:enzymology; D010649:Phenylalanine / Q000031:analogs & derivatives / Q000378:metabolism; D011312:Pressure; D013501:Surface-Active Agents / Q000737:chemistry*; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D008823:Micelles; D009795:Octanes; D013501:Surface-Active Agents; D004143:Dioctyl Sulfosuccinic Acid; C011358:Suphepa; C028121:N-benzyloxycarbonyltyrosine-4-nitrophenyl ester; D014443:Tyrosine; D010649:Phenylalanine; D002918:Chymotrypsin; C026728:octane