Thermokinetic Study on the Reversible Competitive Inhibition of Bovine Liver Arginase  

作　　者：谢修银 汪存信 王志勇 

机构地区：[1]College of Chemistry and Environment Engineering, Yangtze University [2]College of Chemistry and Molecular Science, Wuhan University, Wuhan, Hubei 430072, China

出　　处：《Chinese Journal of Chemistry》2004年第11期1257-1261,共5页中国化学（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (No. 30070200) and the Major Project of Hubei Province; Department of Education; China (No. 2003A009).

摘　　要：A new thermokinetic reduced extent method for studying of the reversible competitive inhibition of single sub-strate enzyme-catalyzed reactions was proposed in this paper. The reaction that arginase-catalyzed hydrolysis of L-arginine to L-ornithine and urea and the inhibition of this reaction by the product, L-ornithine, and exogenous L-lysine were studied at 37 ℃ in 40 mmolL-1 sodium barbiturate-HCl buffer solution (pH=9.4). Michealis con-stant Km for arginine and maximum velocity Vm of the reaction were determined to be 5.14 mmolL-1 and 1.13× 10-2 mmolL-1s-1, respectively. The product inhibition constant KP and inhibitory constant KI of L-lysine were de-termined to be 1.18 and 5.6 mmolL-1, respectively. All the results have better repeatability and self-consistency and are in agreement with literature values. This new method using more direct thermal information from the proc-ess would give more reliable kinetic information than the traditional initial rate method.A new thermokinetic reduced extent method for studying of the reversible competitive inhibition of single sub-strate enzyme-catalyzed reactions was proposed in this paper. The reaction that arginase-catalyzed hydrolysis of L-arginine to L-ornithine and urea and the inhibition of this reaction by the product, L-ornithine, and exogenous L-lysine were studied at 37 ℃ in 40 mmolL-1 sodium barbiturate-HCl buffer solution (pH=9.4). Michealis con-stant Km for arginine and maximum velocity Vm of the reaction were determined to be 5.14 mmolL-1 and 1.13× 10-2 mmolL-1s-1, respectively. The product inhibition constant KP and inhibitory constant KI of L-lysine were de-termined to be 1.18 and 5.6 mmolL-1, respectively. All the results have better repeatability and self-consistency and are in agreement with literature values. This new method using more direct thermal information from the proc-ess would give more reliable kinetic information than the traditional initial rate method.

关 键 词：bovine liver arginase reversible competitive inhibition L-ARGININE L-LYSINE THERMOKINETICS 

分 类 号：O643.3[理学—物理化学]