细交链孢菌酮酸。莴苣叶绿体偶联因子1的非竞争性抑制剂。

Tentoxin. An uncompetitive inhibitor of lettuce chloroplast coupling factor 1.

作者信息

Steele J A, Durbin R D, Uchytil T F, Rich D H

出版信息

Biochim Biophys Acta. 1978 Jan 11;501(1):72-82. doi: 10.1016/0005-2728(78)90096-8.

Abstract

The interaction of tentoxin [cyclo-(-L-leucyl-N-methyl-(Z)-dehydrophenylalanyl-glycyl-N-methyl-L-alanyl-)] with solubilized lettuce chloroplast coupling factor 1 was characterized by direct binding studies, measurement of the time course of ATPase inhibition, and steady-state enzyme kinetics. Neither substrates, products or Ca2+ competed with the tentoxin binding site, nor did they induce any large change in tentoxin affinity. The inhibition of lettuce chloroplast coupling factor 1 ATPase was found to be the time dependent, and at equilibrium the affinities estimated by equilibrium ultrafiltration and enzyme inhibition were similar (1.8 . 10(8) M-1). The steady-state kinetics best fit an uncompetitive pattern suggesting that the inhibited steps follow an irreversible step occurring after ATP binding.

摘要

通过直接结合研究、ATP酶抑制时间进程的测定以及稳态酶动力学，对毒素（环（-L-亮氨酰-N-甲基-（Z）-脱氢苯丙氨酰-甘氨酰-N-甲基-L-丙氨酰-））与溶解的莴苣叶绿体偶联因子1的相互作用进行了表征。底物、产物或Ca2+均不与毒素结合位点竞争，它们也不会引起毒素亲和力的任何大的变化。发现莴苣叶绿体偶联因子1 ATP酶的抑制作用是时间依赖性的，在平衡时，通过平衡超滤和酶抑制估计的亲和力相似（1.8×10^8 M^-1）。稳态动力学最符合非竞争性模式，表明受抑制步骤遵循ATP结合后发生的不可逆步骤。