小麦多酚氧化酶酶学特性的研究

A Study on Zymological Characteristics of Polyphenol Oxidase from Wheat

选取3个小麦品种作为试验材料，以邻苯二酚为底物，采用分光光度法在410nm处测定小麦多酚氧化酶的活性，研究温度、pH值、底物浓度对其活性的影响以及酶促动力学常数Km，结果表明：小麦多酚氧化酶的最适温度范围为60～75℃，最适pH值为4．0～4．6，描述的单底物酶促反应动力学，相应的动力学参数Km=0．19mol/L，vmax=4．04×10^2（mol·L^-1）·min^-1。

The properties of polyphenol oxidase extracted from wheat were investigated. Three wheat varieties were selected as experimental materials and catechol was used as substrate. The activity of wheat polyphenol oxidase was determined by spectrophotometry at 410 nm, thus to study the effects of pit, temperature, substrate concentration and enzyme concentration on its activity as well as the enzymatic reaction kinetic constant Km. the results showed that the optimum temperature and pH of wheat polyphonel oxidase was 60～75℃ and 4.0-4.6 respectively. The enzymatic reaction kinetics of single substrate was accordant with Michaelis equation, corresponding kinetic parameter Km =0.19 mol/L, Vmax=4.04 × 10^2 mol/min.