Studies on the Inactivation of Bovine Liver Enoyl-CoA Hydratase by (Methylenecyclopropyl)formyl-CoA: Elucidation of the Inactivation Mechanism and Identification of Cysteine-114 as the Entrapped Nucleophile
作者:Srikanth Dakoji、Ding Li、Gautam Agnihotri、Hui-qiang Zhou、Hung-wen Liu
DOI:10.1021/ja011226k
日期:2001.10.1
(R)- and (S)-diastereomers of MCPF-CoA to examine the stereoselectivity of this inactivation. Both compounds were shown to be competent inhibitors for bovine liver ECH with nearly identical second-order inactivation rate constants (k(inact)/K(I)) and partition ratios (k(cat)/k(inact)), indicating that the inactivation is nonstereospecific with respect to ring cleavage. The inhibitor, upon incubation
(亚甲基环丙基)甲酰辅酶 A (MCPF-CoA) 是一种天然氨基酸(亚甲基环丙基)甘氨酸的代谢物,对牛肝烯酰辅酶 A 水合酶 (ECH) 的抑制特性进行了表征。我们之前已经证明 MCPF-CoA 专门针对 ECH,它催化 alpha,beta-不饱和烯酰-CoA 底物可逆地水合为相应的 β-羟酰基-CoA 产物。在这里,我们合成了 MCPF-CoA 的 (R)-和 (S)-非对映异构体,以检查这种失活的立体选择性。两种化合物均被证明是牛肝 ECH 的有效抑制剂,具有几乎相同的二级失活速率常数 (k(inact)/K(I)) 和分配比 (k(cat)/k(inact)),表明失活在环裂解方面是非立体特异性的。抑制剂,与牛肝 ECH 孵育后,在蛋白质活性位点附近标记胰蛋白酶肽 ALGGGXEL,其中 X 是共价修饰的氨基酸。牛肝 ECH 基因的克隆和序列分析揭示了被 MCPF-CoA 捕获的氨基酸残基的身份为