Clark D D, Daggett S G, Schuster S M
Arch Biochem Biophys. 1984 Sep;233(2):378-92. doi: 10.1016/0003-9861(84)90459-4.
The pre-steady-state kinetics of beef heart mitochondrial ATPase (F1) were examined. F1 was found to exhibit hysteretic behavior when hydrolyzing ATP. The hysteretic property was expressed as an activation process which occurred when the enzyme was mixed with its substrate, MgATP. Many catalytic turnovers were required before the activation was complete. The lag in hydrolysis increased hyperbolically as the concentration of enzyme increased. Passage of F1 through Sephadex G25 eliminated the activation process. Several kinetically distinct possibilities for explaining these data, including multiple nucleotide dissociations, enzyme conformational changes, and regulatory site interactions, are discussed. The enzyme was apparently able to recognize nucleotide in a noncatalytic manner, as evidenced by the fact that F1 preincubated with ADP in the absence of substrate achieved partial activation (smaller lag times) before being introduced to substrate. ADP is also a time-dependent inhibitor, exhibiting a slow hysteretic inhibition in addition to immediate competitive inhibition.
对牛心线粒体ATP酶（F1）的预稳态动力学进行了研究。发现F1在水解ATP时表现出滞后行为。这种滞后特性表现为一种激活过程，当酶与其底物MgATP混合时发生。在激活完成之前需要许多催化周转。随着酶浓度的增加，水解滞后呈双曲线增加。F1通过葡聚糖凝胶G25消除了激活过程。讨论了几种从动力学角度解释这些数据的不同可能性，包括多个核苷酸解离、酶构象变化和调节位点相互作用。该酶显然能够以非催化方式识别核苷酸，这一事实证明，在不存在底物的情况下用ADP预孵育的F1在引入底物之前实现了部分激活（滞后时间更短）。ADP也是一种时间依赖性抑制剂，除了立即竞争性抑制外，还表现出缓慢的滞后抑制。
