Daggett S G, Tomaszek T A, Schuster S M
Arch Biochem Biophys. 1985 Feb 1;236(2):815-24. doi: 10.1016/0003-9861(85)90688-5.
This study examined the inhibition of azide as a probe of the magnesium regulation of beef heart mitochondrial ATPase (F1) catalysis. Azide elicited a slow hysteretic effect on both ATP and ITP hydrolysis of F1. This hysteretic effect was shown to be due to the consecutive binding of magnesium and azide, and to be independent of catalytic turnover. The azide binding site was also shown to be separate from the anion binding HCO3- site on F1. The results presented indicate that metal binding is important in the inhibition of the hydrolytic activity and regulation of F1. A model is presented which is consistent with the hysteretic inhibition of F1 by azide, in which there is a slow equilibration between free enzyme and the enzyme-magnesium-azide complex.
本研究以叠氮化物的抑制作用作为探究牛肉心线粒体ATP酶（F1）催化过程中镁离子调控的探针。叠氮化物对F1的ATP和ITP水解均产生了缓慢的滞后效应。该滞后效应被证明是由于镁离子和叠氮化物的连续结合所致，且与催化周转无关。叠氮化物结合位点也被证明与F1上的阴离子结合位点HCO3-不同。研究结果表明，金属结合在抑制F1水解活性及调控过程中起着重要作用。本文提出了一个与叠氮化物对F1的滞后抑制作用相符的模型，其中游离酶与酶-镁离子-叠氮化物复合物之间存在缓慢的平衡。
