产维生素B12的肺炎克雷伯菌IFO 13541中的天冬氨酸脱氢酶

Aspartate dehydrogenase in vitamin B12-producing Klebsiella pneumoniae IFO 13541.

作者信息

Okamura T, Noda H, Fukuda S, Ohsugi M

机构信息

Department of Food Science and Nutrition, School of Human Environmental Sciences, Mukogawa Women's University, Nishinomiya, Japan.

出版信息

J Nutr Sci Vitaminol (Tokyo). 1998 Aug;44(4):483-90. doi: 10.3177/jnsv.44.483.

DOI:10.3177/jnsv.44.483

PMID:9819709

Abstract

We found a new reaction of aspartic acid dehydrogenation, catalyzed by NADP(+)-dependent aspartate dehydrogenase, in vitamin B12-producing Klebsiella pneumoniae IFO 13541. The enzyme, which was purified from a crude extract of K.pneumoniae IFO 13541, catalyzes the oxidative deamination of aspartic acid to form oxaloacetic acid. This enzyme had a molecular mass of about 124 kDa consisting of two identical subunits. L-Aspartic acid was a substrate, although D-aspartic acid and L-glutamic acid were inactive. The enzyme showed maximal activity at about pH 7.0-8.0 for the oxidative deamination of L-aspartic acid, and it required NADP+ as a coenzyme, while NAD+ was inactive.

摘要

我们在产维生素B12的肺炎克雷伯菌IFO 13541中发现了一种由NADP(+)-依赖性天冬氨酸脱氢酶催化的天冬氨酸脱氢新反应。该酶从肺炎克雷伯菌IFO 13541的粗提物中纯化得到，催化天冬氨酸的氧化脱氨反应生成草酰乙酸。这种酶的分子量约为124 kDa，由两个相同的亚基组成。L-天冬氨酸是底物，而D-天冬氨酸和L-谷氨酸无活性。该酶在pH约7.0 - 8.0时对L-天冬氨酸的氧化脱氨反应表现出最大活性，并且需要NADP+作为辅酶，而NAD+无活性。