松鼠猴肝脏乙醇脱氢酶：松鼠猴中同工酶的分离与特性分析

Simian liver alcohol dehydrogenase: isolation and characterization of isoenzymes from Saimiri sciureus.

作者信息

Dafeldecker W P, Parés X, Vallee B L, Bosron W F, Li T K

出版信息

Biochemistry. 1981 Feb 17;20(4):856-61. doi: 10.1021/bi00507a031.

Abstract

The alcohol dehydrogenase (ADH) of squirrel monkey liver can be purified and separated into pyrazole-insensitive and pyrazole-sensitive isoenzymes by affinity chromatography. This is the first demonstration of two functionally distinct classes of ADH in a species other than man. The inhibition of the two enzyme fractions by 4-methylpyrazole is analogous to that observed for the corresponding isoenzymes of human liver. Similarly, the substrate specificity of the pyrazole-insensitive form is more limited and its Km for ethanol (4 mM at pH 7.5) and acetaldehyde (11 mM at pH 7.0) is larger than that of the pyrazole-sensitive isoenzymes. However, their physicochemical and compositional characteristics, i.e., molecular weight, zinc content, and dimeric structure, are all virtually identical with those of other mammalian alcohol dehydrogenases studied thus far. Zinc is essential for the enzymatic function of both molecular forms as demonstrated by inhibition with chelating agents.

摘要

松鼠猴肝脏中的乙醇脱氢酶（ADH）可通过亲和色谱法进行纯化，并分离为对吡唑不敏感和对吡唑敏感的同工酶。这是在人类以外的物种中首次证明存在两种功能不同的ADH类别。4-甲基吡唑对这两种酶组分的抑制作用与在人肝脏相应同工酶中观察到的情况相似。同样，对吡唑不敏感形式的底物特异性更有限，其对乙醇（pH 7.5时为4 mM）和乙醛（pH 7.0时为11 mM）的Km大于对吡唑敏感的同工酶。然而，它们的物理化学和组成特征，即分子量、锌含量和二聚体结构，实际上与迄今为止研究的其他哺乳动物乙醇脱氢酶的特征完全相同。如用螯合剂抑制所表明的，锌对于两种分子形式的酶功能都是必不可少的。