Biochemical kinetics of skeletal actosubfragment-1 at high subfragment-1 concentrations.
Biochemical kinetics of skeletal actosubfragment-1 at high subfragment-1 concentrations.
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高 subfragment-1 浓度下骨骼 actosubfragment-1 的生化动力学。
DOI：
10.1016/s0006-3495(89)82672-4
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发表时间：
1989
影响因子：
3.4
通讯作者：
Harwalkar,VA
中科院分区：
文献类型：
--
作者：
Stein,LA;Harwalkar,VA
骨骼肌球蛋白亚片段-1（S-1）的肌动球蛋白ATP酶活性通常通过保持S-1浓度较低并改变肌动蛋白浓度来研究。一般协议存在的动力学数据观察。研究ATP酶活性的另一种方法是保持肌动蛋白浓度较低，并改变S-1浓度。已经出现的图像是，最大ATP酶速率（每微摩尔肌动蛋白），Vamax，是固定S-1时测量的Vsmax的几倍。同样，表观活化常数Kam比KATP酶弱几倍。此外，它被发现，卡姆，此后卡姆（At），随着总的肌动蛋白浓度At，但争论继续对肌动蛋白依赖的VAMAX。特别令人感兴趣的事实是，格伦-泰勒和不应状态模型不能解释的数据。在此，我们对固定肌动蛋白浓度下的ATP酶活性进行了重复研究，试图确定目前的肌动蛋白激活肌球蛋白ATP酶活性模型是否可以同时解释恒定肌动蛋白和恒定S-1数据，或者这些数据是否意味着需要假设新的动力学模型。我们的结论是，目前的动力学模型可以解释的数据。
The actomyosin ATPase activity of skeletal myosin subfragment-1 (S-1) is typically studied by keeping the S-1 concentration low and varying the actin concentration. General agreement exists over the kinetic data observed. Another way of studying the ATPase activity is to keep the actin concentration low and vary the S-1 concentration. The picture that has emerged is that the maximal ATPase rate (per micromolar actin), Vamax, is several fold greater than the Vsmax measured at fixed S-1. Likewise, the apparent activation constant Kam is several fold weaker than KATPase. In addition it is found that Kam, henceforth Kam(At), varies with the total actin concentration At, but controversy continues over the actin dependence of Vamax. Of particular interest is the fact that the Lymn-Taylor and refractory state models could not account for the data. Here we have repeated studies on the ATPase activity at fixed actin concentration in an attempt to determine if the current models for the actin activated myosin ATPase activity can account for both the constant actin and constant S-1 data simultaneously, or if these data imply that new kinetic models need be postulated. We conclude that the current kinetic models can account for the data.