粗糙脉孢菌α-酮戊二酸脱氢酶复合体：描述、组分解析及催化特性

Neurospora crassa alpha-ketoglutarate dehydrogenase complex: description, resolution of components and catalytic properties.

作者信息

Bessam H, Mareck A M, Foucher B

机构信息

Laboratoire de Biochimie, Unité Associée au CNRS No. 203, Faculté des Sciences, Université de Rouen Haute-Normandie, Mont-Saint-Aignan, France.

出版信息

Biochim Biophys Acta. 1989 Jan 27;990(1):66-72. doi: 10.1016/s0304-4165(89)80013-3.

DOI:10.1016/s0304-4165(89)80013-3

PMID:2521564

Abstract

A method is proposed for the purification of the Neurospora crassa alpha-ketoglutarate dehydrogenase complex, and the main points for preserving its activity, which seems to be particularly fragile in fungus, are discussed. Resolution of the constitutive enzymes was attempted and permitted the identification of the three protein bands resolved on SDS-polyacrylamide gel electrophoresis as E3, E1 and E2 with respective Mr values of 54,000, 53,000 and 49,000. Catalytic properties of the purified complex were established showing the importance of divalent cations in regulating the activity level. The role of Ca2+ in particular was investigated. It was shown that Ca2+ diminishes the Km value of the N. crassa alpha-ketoglutarate dehydrogenase complex for alpha-ketoglutarate in the physiological concentration range, as previously observed for the mammalian complexes.

摘要

本文提出了一种纯化粗糙脉孢菌α-酮戊二酸脱氢酶复合体的方法，并讨论了在真菌中似乎特别脆弱的该复合体活性的主要保存要点。尝试对组成型酶进行分离，并确定了在SDS-聚丙烯酰胺凝胶电泳上分离出的三条蛋白带分别为E3、E1和E2，其各自的Mr值分别为54,000、53,000和49,000。确定了纯化复合体的催化特性，表明二价阳离子在调节活性水平方面的重要性。特别研究了Ca2+的作用。结果表明，在生理浓度范围内，Ca2+降低了粗糙脉孢菌α-酮戊二酸脱氢酶复合体对α-酮戊二酸的Km值，这与之前在哺乳动物复合体中观察到的情况一致。