辣根过氧化物酶催化丙二醛氧化的机制。

Mechanism of horseradish peroxidase-catalyzed oxidation of malonaldehyde.

作者信息

MacDonald I D, Dunford H B

机构信息

Department of Chemistry, University of Alberta, Edmonton, Canada.

出版信息

Arch Biochem Biophys. 1989 Jul;272(1):185-93. doi: 10.1016/0003-9861(89)90209-9.

DOI:10.1016/0003-9861(89)90209-9

PMID:2735762

Abstract

The mechanism of malonaldehyde oxidation by horseradish peroxidase in the presence of manganese(II) and acetate was investigated. Our results show that an apparent oxygenase behavior demonstrated by peroxidase in this system can be explained in terms of normal peroxidase activity. A free radical is generated from the reaction of malonaldehyde with compounds I and II of peroxidase; this radical is scavenged by dissolved molecular oxygen to give the appearance of peroxidase acting as an oxygenase. Oxygen consumption, absorbance spectra, and kinetic results show that the reaction is initiated by autoxidation of malonaldehyde to give a free radical. The radical reacts with oxygen and through the action of manganese(II), a peroxide is generated. This peroxide drives the peroxidase cycle to generate more free radicals which propagate the oxygen consumption reaction.

摘要

研究了在锰（II）和乙酸盐存在下辣根过氧化物酶催化丙二醛氧化的机制。我们的结果表明，该系统中过氧化物酶表现出的明显加氧酶行为可以用正常的过氧化物酶活性来解释。丙二醛与过氧化物酶的化合物I和II反应产生自由基；该自由基被溶解的分子氧清除，从而使过氧化物酶表现出加氧酶的作用。氧气消耗、吸收光谱和动力学结果表明，该反应由丙二醛的自氧化引发，产生自由基。该自由基与氧气反应，并通过锰（II）的作用生成过氧化物。这种过氧化物驱动过氧化物酶循环以产生更多自由基，从而促进氧气消耗反应。