辅酶A生物合成：4'-磷酸泛酰巯基乙胺-L-半胱氨酸脱羧酶的立体化学过程。

Coenzyme A biosynthesis: steric course of 4'-phosphopantothenoyl-L-cysteine decarboxylase.

作者信息

Aberhart D J, Ghoshal P K, Cotting J A, Russell D J

出版信息

Biochemistry. 1985 Dec 3;24(25):7178-82. doi: 10.1021/bi00346a024.

Abstract

4'-Phosphopantothenoyl-L-cysteine decarboxylase (PPC decarboxylase) was partially purified from rat liver. 4'-Phosphopantothenoyl[2-2H1]-L-cysteine was synthesized and converted by PPC decarboxylase to 4'-phosphol[1-2H1]pantetheine. The product was degraded by reduction with Raney nickel followed by acidic hydrolysis to [1-2H1]ethylamine. The latter was converted to the (-)-camphanamide derivative, NMR studies of which revealed that the deuterium was located in the pro-1S position. Also, unlabeled 4'-phosphopantothenoyl-L-cysteine was incubated with PPC decarboxylase in D2O, giving, after degradation, the (-)-camphanamide of (1R)-[1-2H1]ethylamine. The results show that the decarboxylation takes place with retention of configuration. These results are discussed in terms of possible mechanisms for the decarboxylation.

摘要

4'-磷酸泛酰-L-半胱氨酸脱羧酶（PPC脱羧酶）从大鼠肝脏中部分纯化出来。合成了4'-磷酸泛酰[2-²H₁]-L-半胱氨酸，并通过PPC脱羧酶将其转化为4'-磷酸[1-²H₁]泛酰巯基乙胺。产物经雷尼镍还原后再进行酸性水解，降解为[1-²H₁]乙胺。后者转化为(-)-樟脑酰胺衍生物，对其进行核磁共振研究表明氘位于前-1S位置。此外，将未标记的4'-磷酸泛酰-L-半胱氨酸与PPC脱羧酶在重水中孵育，降解后得到(1R)-[1-²H₁]乙胺的(-)-樟脑酰胺。结果表明脱羧反应发生时构型保持不变。根据脱羧反应可能的机制对这些结果进行了讨论。