Barski O A, Watanabe K
Department of Enzyme and Metabolism, Osaka Bioscience Institute, Japan.
FEBS Lett. 1993 Apr 5;320(2):107-10. doi: 10.1016/0014-5793(93)80072-3.
The kinetic mechanism of ketoreductase activity of bovine lung prostaglandin F synthase, expressed in E. coli, was investigated. Data on initial velocity and radioisotope exchange between [3H]prostaglandin D2 and 9 alpha,11 beta-prostaglandin F2 suggest that the enzyme obeys the ping-pong mechanism. Using a fluorescence technique we obtained a binding constant of 3 microM for NADPH. This is in close correlation with the kinetically determined intrinsic Michaelis constant for NADPH. Activation energy of the redox process was determined from the temperature dependence of maximal velocities for nitrobenzaldehyde and menadione and was found to be 119 and 96 kJ/mol, respectively.
对在大肠杆菌中表达的牛肺前列腺素F合酶的酮还原酶活性的动力学机制进行了研究。关于[3H]前列腺素D2与9α,11β-前列腺素F2之间的初速度和放射性同位素交换的数据表明，该酶遵循乒乓机制。使用荧光技术，我们获得了NADPH的结合常数为3 microM。这与动力学测定的NADPH的内在米氏常数密切相关。氧化还原过程的活化能由对硝基苯甲醛和甲萘醌最大速度的温度依赖性确定，分别为119和96 kJ/mol。
