纤细裸藻中参与钴胺素脱氰作用的钴胺素还原酶（NADPH；消除氰基）的发生与特性

Occurrence and characterization of cyanocobalamin reductase (NADPH; CN-eliminating) involved in decyanation of cyanocobalamin in Euglena gracilis.

作者信息

Watanabe F, Oki Y, Nakano Y, Kitaoka S

机构信息

Department of Agricultural Chemistry, University of Osaka Prefecture, Japan.

出版信息

J Nutr Sci Vitaminol (Tokyo). 1988 Feb;34(1):1-10. doi: 10.3177/jnsv.34.1.

DOI:10.3177/jnsv.34.1

PMID:3134526

Abstract

The activity of an enzyme involved in decyanation of cyanocobalamin was found in the cell homogenate of Euglena gracilis. The enzyme essentially required FAD or FMN, and NADPH as cofactors. The apparent Km for cyanocobalamin and NADPH were 7.1 microM and 0.2 mM, respectively. The enzyme reaction obeyed allosteric kinetics towards FAD ([FAD]0.5 = 30 microM, n = 2.7; as calculated by the Hill plots). The Euglena enzyme was located in the mitochondria.

摘要

在纤细裸藻的细胞匀浆中发现了一种参与钴胺素脱氰作用的酶的活性。该酶本质上需要FAD或FMN以及NADPH作为辅因子。钴胺素和NADPH的表观Km分别为7.1微摩尔和0.2毫摩尔。该酶反应对FAD呈现别构动力学（[FAD]0.5 = 30微摩尔，n = 2.7；通过希尔图计算）。裸藻的这种酶定位于线粒体中。