Sigalat C, Pitard B, Haraux F
Section de Bioénergétique, DBCM-CEA Saclay, Gif-sur-Yvette, France.
FEBS Lett. 1995 Jul 17;368(2):253-6. doi: 10.1016/0014-5793(95)00664-u.
The effect of tentoxin at high concentrations was investigated in thylakoids and proteoliposomes containing bacteriorhodopsin and CF0CF1. Venturicidin-sensitive ATP hydrolysis, ATP-generated delta pH and ATP synthesis were practically 100% inhibited at 2 microM tentoxin, and restored to various extents beyond 50 microM. With respect to the native enzyme, tentoxin-reactivated ATPase had the following properties: (i) a higher delta pH requirement to synthetise ATP; (ii) a decreased futile proton flow through CF0CF1 (without ADP), which remains 100% blocked by ADP. It is concluded that despite its altered kinetic performances, tentoxin-modified CF0CF1 preserves its mechanism and remains a tightly coupled proton pump.
研究了高浓度鱼藤酮对含有细菌视紫红质和CF0CF1的类囊体和蛋白脂质体的影响。在2微摩尔鱼藤酮作用下,对venturicidin敏感的ATP水解、ATP产生的ΔpH值和ATP合成实际上被100%抑制,而在50微摩尔以上则不同程度恢复。相对于天然酶,鱼藤酮重新激活的ATP酶具有以下特性:(i)合成ATP需要更高的ΔpH值;(ii)通过CF0CF1(无ADP)的无效质子流减少,而ADP仍能100%阻断该质子流。得出的结论是,尽管其动力学性能发生了改变,但鱼藤酮修饰的CF0CF1保留了其机制,仍然是一个紧密偶联的质子泵。