豌豆二胺氧化酶解离常数的测定

Determination of the dissociation constants of pea diamine oxidase.

作者信息

Pec P, Haviger A, Frébort I

机构信息

Department of Analytical and Organic Chemistry, Faculty of Science, Palacký University, Czechoslovakia.

出版信息

Biochem Int. 1992 Feb;26(1):87-96.

PMID:1616501

Abstract

The activity of diamine oxidase [EC 1.4.3.6] (DAO) isolated from pea cotyledons was measured in Britton-Robinson buffers at pH range 5.0-9.6 by spectrophotometric method with E-1,4-diamino-2-butene as substrate. The enzyme has the highest activity at pH = 7.7 and in pH greater than 8.0 it is irreversible denaturated with time. The dissociation constants of the enzyme and enzyme-substrate complex were calculated by Dixon's method from plots of log Vmax, log KM and log Vmax/KM against pH. The pKEA = 6.5 suggests that histidine is in active site of DAO.

摘要

以E-1,4-二氨基-2-丁烯为底物，采用分光光度法，在pH值为5.0 - 9.6的Britton-Robinson缓冲液中测定从豌豆子叶中分离出的二胺氧化酶EC 1.4.3.6的活性。该酶在pH = 7.7时具有最高活性，在pH大于8.0时会随时间发生不可逆变性。通过Dixon方法，根据log Vmax、log KM和log Vmax/KM对pH的曲线计算酶和酶-底物复合物的解离常数。pKEA = 6.5表明组氨酸位于DAO的活性位点。