Abstract: The kinetics of hydrolysis of cytidine 2',3'-cyclic phosphate(CP) catalyzed by ribonuclease A(RNase A) solubilized in reverse micelles formed by dodecylammonium butyrate(DAB) in cyclohexane has been investigated. The results show that the Michaelis-Menten law can be applied to DAB-cyclohexane reverse micellar solutions as well as to aqueous solutions. The enzyme efficiency(expressed in terms of the ratio k_cat/k_m) of RN ase A solubilized in DAB cyclohexane reverse micellar solutions is 14—30 times of that in aqueous solution. Under the conditions at constant concentration of DAB as well as at constant molecular ratio of H₂O and DAB, the enzymetic activity of RN ase A in reverse micellar solutions decreases as the water content is increased. The results were explained briefly in terms of the changes in the conformation of the enzyme as well as in the concentrations of the enzyme and the substrate in inner water phase.

Key words: Ribonuclease A, Dodecylammonium butyrate, Reverse micelle, Michaelis-Menten law, Catalysis kinetics of enzyme