细菌丁酰辅酶A脱氢酶中的内在巴豆酸酶活性。

Intrinsic crotonase activity in a bacterial butyryl-CoA dehydrogenase.

作者信息

Ellison P A, Engel P C

机构信息

Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, U.K.

出版信息

Biochem Mol Biol Int. 1993 Mar;29(4):605-12.

PMID:8490573

Abstract

Butyryl-CoA, crotonyl-CoA or 3-hydroxybutyryl-CoA all ultimately form an enzyme-acetoacetyl-CoA complex upon aerobic addition to butyryl-CoA dehydrogenase purified from Megasphaera elsdenii, implying the presence of crotonase activity. This behaviour remains even after treatment with 6M urea, which destroys the activity of the main crotonase fraction from M. elsdenii. Flavin-sensitised photoinactivation destroys residual crotonase and dehydrogenase activities in parallel. Butyryl-CoA dehydrogenase thus has intrinsic crotonase activity with a turnover rate (0.05 min-1) about 0.02% of the figure for dehydrogenase activity. Mechanistic implications are discussed.

摘要

丁酰辅酶A、巴豆酰辅酶A或3-羟基丁酰辅酶A在需氧条件下添加到从埃氏巨球型菌纯化的丁酰辅酶A脱氢酶中时，最终都会形成一种酶-乙酰乙酰辅酶A复合物，这意味着存在巴豆酸酶活性。即使在用6M尿素处理后，这种行为仍然存在，6M尿素会破坏埃氏巨球型菌主要巴豆酸酶组分的活性。黄素敏化光失活会同时破坏残留的巴豆酸酶和脱氢酶活性。因此，丁酰辅酶A脱氢酶具有内在的巴豆酸酶活性，其周转速率（0.05分钟-1）约为脱氢酶活性数值的0.02%。文中讨论了其机制含义。