Biochemical kinetics of porcine cardiac subfragment-1. II. Pre-steady-state studies of the initial phosphate burst.
Biochemical kinetics of porcine cardiac subfragment-1. II. Pre-steady-state studies of the initial phosphate burst.
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猪心脏亚片段-1的生化动力学。
DOI：
10.1161/01.res.65.2.515
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发表时间：
1989
影响因子：
20.1
通讯作者：
Annis,DT
中科院分区：
文献类型：
--
作者：
Stein,LA;White,MP;Annis,DT
肌动蛋白的依赖性的速率和幅度的初始磷酸盐突发使用淬火流和停流动力学技术。这些研究表明，即使在高浓度的肌动蛋白磷酸爆发的幅度是一个显着的分数的幅度存在于肌动蛋白的情况下。此外，它表明，爆发的速度迅速上升作为肌动蛋白浓度的函数。四态模型的详细建模表明，如果预测的Vmax被约束为近似等于外推值，（双倒数图），如果亚片段-1与肌动蛋白的表观解离常数除以肌动蛋白激活的肌球蛋白ATP酶活性的表观激活常数，（K结合/K ATP酶）被限制为与一个显著不同，则该模型不能同时解释ATP酶活性和初始无机磷酸盐爆发的速率和幅度。
The actin dependence of the rate and magnitude of the initial phosphate burst was measured using both quench-flow and stopped-flow kinetic techniques. These studies revealed that even at high actin concentrations the magnitude of the phosphate burst was a significant fraction of the magnitude that exists in the absence of actin. Furthermore, it was shown that the rate of the burst rises rapidly as a function of the actin concentration. Detailed modeling with the four-state model revealed that if the predicted Vmax is constrained to be approximately equal to the extrapolated value (double reciprocal plot) and if the apparent dissociation constant of subfragment-1 to actin divided by the apparent activation constant of the actin-activated myosin ATPase activity (Kbinding/KATPase) is constrained to be considerably different from one, then the model is unable to simultaneously account for the ATPase activity and the rate and magnitude of the initial inorganic phosphate burst.