短柄棒杆菌胆固醇氧化酶催化的异构化反应在一个碱基作用下具有立体特异性地进行。

The isomerization catalyzed by Brevibacterium sterolicum cholesterol oxidase proceeds stereospecifically with one base.

作者信息

Kass I J, Sampson N S

机构信息

Department of Chemistry, State University of New York at Stony Brook 11794-3400.

出版信息

Biochem Biophys Res Commun. 1995 Jan 17;206(2):688-93. doi: 10.1006/bbrc.1995.1097.

DOI:10.1006/bbrc.1995.1097

PMID:7826388

Abstract

We have demonstrated that the isomerization reaction catalyzed by Brevibacterium sterolicum (ATCC 81387) cholesterol oxidase (EC 1.1.3.6) proceeds via a stereospecific proton transfer from the 4 beta carbon to the 6 beta carbon to form 4-cholestene-3-one using deuterated and nondueterated substrates. This result implies that there is one active site base, positioned over the beta-face, responsible for isomerization. On the basis of X-ray crystallographic evidence [Li, J., Vrielink, A., Brick, P. & Blow, D. M. Biochemistry 32, 11507-11515 (1993)], glutamate-361 is the most likely candidate for this general base.

摘要

我们已经证明，短柄棒杆菌（ATCC 81387）胆固醇氧化酶（EC 1.1.3.6）催化的异构化反应通过从4β碳到6β碳的立体特异性质子转移进行，使用氘代和非氘代底物形成4-胆甾烯-3-酮。这一结果表明，在β面上方存在一个负责异构化的活性位点碱基。根据X射线晶体学证据[Li, J., Vrielink, A., Brick, P. & Blow, D. M. Biochemistry 32, 11507-11515 (1993)]，谷氨酸-361最有可能是这个通用碱基的候选者。