Microcalorimetric Study on Tyrosine Oxidation Catalyzed by Tyrosinase  

作　　者：JunYAO YiLIU TianZhiWANG JianBenLIU PengLIU ZiNiuYU 

机构地区：[1]KeyLaboratoryofMicrobiologyofChineseAgriculturalMinistry,HuazhongAgriculturalUniversity,Wuhan430070 [2]CollegeofChemistryandMolecularScience,WuhanUniversity,Wuhan430072 [3]CollegeofLifeScienceandChemistry,JishouUniversity,Jishou416000

出　　处：《Chinese Chemical Letters》2003年第6期619-622,共4页中国化学快报（英文版）

基　　金：This work were supported by the National Natural Science Foundation of China(No.30170010,29973030);The Teaching and Research Award Program for Outstanding Young Professors in High Education Institute,MOE,China(2001).

摘　　要：Through the method of initial heat release rate, the kinetic property of tyrosine oxidation catalyzed by tyrosinase from Pseudomonas maltophilia was investigated using a LKB-2107 batch microcalorimeter. Tyrosine was catalyzed and oxidized into L-dopa, then into melanin catalyzed by tyrosinase. We found that the tyrosinase reaction obeyed the Michaelis-Menten kinetics, and at 298.15K and pH 7.0, the initial exothermic rate (W0 ) are in the range of 0.1567~0.5704 mJ·s-1, the maximum exothermic rate (Wmax) are in 0.4152 ~ 0.8143mol·L-1, and mean value of the Michaelis constant (Km) is 2.199±0.105104 mol·L-1.Through the method of initial heat release rate, the kinetic property of tyrosine oxidation catalyzed by tyrosinase from Pseudomonas maltophilia was investigated using a LKB-2107 batch microcalorimeter. Tyrosine was catalyzed and oxidized into L-dopa, then into melanin catalyzed by tyrosinase. We found that the tyrosinase reaction obeyed the Michaelis-Menten kinetics, and at 298.15K and pH 7.0, the initial exothermic rate (W0 ) are in the range of 0.1567~0.5704 mJ·s-1, the maximum exothermic rate (Wmax) are in 0.4152 ~ 0.8143mol·L-1, and mean value of the Michaelis constant (Km) is 2.199±0.105104 mol·L-1.

关 键 词：TYROSINE tyrosinase-catalyzed oxidation reaction MICROCALORIMETRY thermokinetics. 

分 类 号：O629.711[理学—有机化学]