氰诱导碳酸酐酶中γ-谷氨酰与咪唑的交联。一种独特的抑制模式。

Cyanogen-induced gamma-glutamyl to imidazole cross-link in carbonic anhydrase. A unique mode of inhibition.

作者信息

Kirley J W, Day R A, Kreishman G P

出版信息

FEBS Lett. 1985 Dec 2;193(2):145-9. doi: 10.1016/0014-5793(85)80139-3.

Abstract

The irreversible inhibition of carbonic anhydrase by cyanogen occurs by a unique mechanism. Cyanogen is an affinity label: it behaves like a carbodiimide and produces an intra-molecular cross-link without being incorporated. The nucleophile-labile cross-link is formed between a gamma-COOH of a Glu and an imidazole of a His with a 1:1:1 stoichiometry with the enzyme. The deletion of approximately 1 Glu and approximately 1 His was noted by amino acid analysis of enzymatically hydrolyzed carbonic anhydrase. The modified Glu was converted to 2,4-diaminobutanoic acid and quantitated by amino acid analysis. The presence and quantity of modified His was supported through high-resolution proton NMR analysis.

摘要

氰对碳酸酐酶的不可逆抑制作用通过一种独特的机制发生。氰是一种亲和标记物：它的行为类似于碳二亚胺，能产生分子内交联而不被掺入。亲核不稳定交联在谷氨酸的γ-羧基和组氨酸的咪唑之间形成，与酶的化学计量比为1:1:1。通过对酶促水解的碳酸酐酶进行氨基酸分析，发现大约缺失了1个谷氨酸和1个组氨酸。修饰后的谷氨酸转化为2,4-二氨基丁酸，并通过氨基酸分析进行定量。通过高分辨率质子核磁共振分析证实了修饰组氨酸的存在和数量。