米糠过氧化物酶的酶学性质研究

摘要

以邻苯二胺、过氧化氢为底物，采用分光光度计测定氧化产物的方法对米糠过氧化物酶的性质进行了研究，结果表明：过氧化物酶活性在35℃达到最大值，最适pH值为6．5，在反应5 min时，达到酶的最大反应活度；金属离子钾、钠、钙对过氧化物酶有不同程度的抑制作用，抑制作用表现为钙离子＞钠离子＞钾离子，木瓜蛋白酶和抗坏血酸在不同范围下呈现出不同的抑制和促进作用。由Linewear -Burk方程，得到过氧化氢Vmax ＝9．708×10-3△A/min，Km ＝15．135×10-3 mol/L；邻苯二胺的Vmax ＝12．346×10-3△A/min，Km ＝19．247×10-3 mol/L。%Taking o-phenylendiamine and hydrogen peroxide as substrates , we researched the enzymatic properties of peroxi-dase collected from rice bran by detecting oxidative products with spectrophotometer .The results indicated that the optimum temper-ature for the activity of peroxidase was 35℃, the optimal pH-value was 6.5, and the optimum reaction time was 5 min.The metal ions K +, Na+and Ca2+had various inhibition on peroxidase , and their inhibitory intensity revealed the following order: Ca2+>Na+>K+.The different concentrations of papain and ascorbic acid showed inhibitory or promotive functions on this enzyme .Ac-cording to the built Linewear -Burk equation, the Vmaxof hydrogen peroxide was 9.708 ×10 -3△A/min, and its Km was 15.135 × 10 -3 mol/L;the Vmax of o-phenylendiamine was 12.346 ×10-3△A/min, and its Km was 19.247 ×10 -3 mol/L.