The Mechanochemistry of Muscular Contraction
The Mechanochemistry of Muscular Contraction
复制标题
肌肉收缩的力学化学
DOI：
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发表时间：
1960
期刊：
影响因子：
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通讯作者：
A. Siger
中科院分区：
文献类型：
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作者：
F. D. Carlson;A. Siger
在碘乙酸氮中毒的肌肉中，PC 1和ATP 1去磷酸化对等长收缩次数的依赖性已经被检查。三磷酸腺苷没有净去磷酸化。PC去磷酸化随抽搐次数线性变化，并产生等量的C1和P1i.1碘乙酸盐浓度，其阻断酶肌酸磷酸激酶，使肌肉不可收缩。值为0.286 µmole/gm。对于每次抽搐的PC分裂量，得到的值为-9.62千卡/摩尔的PC的“生理”水解热与基于热化学数据的预期一致。在一次最大等长收缩中，估计每个肌球蛋白分子有2 ~ 3个PC分子去磷酸化，或每个肌动蛋白分子有1个PC分子去磷酸化。这些结果支持这样的观点，即在这些实验的条件下，PC脱磷酸化是净能量产生反应。这些研究揭示的收缩的机械化学在体内的化学计量，以及已知的化学计量的肌动蛋白聚合和其耦合的肌酸磷酸激酶系统的另一方面是惊人的相似，并强烈表明，可逆的肌动蛋白聚合是参与在一个主要的方式在肌肉的收缩-松弛-恢复周期。
The dependence of PC1 and ATP1 dephosphorylation on the number of isometric twitches in the iodoacetate-nitrogen-poisoned muscle has been examined. There is no net dephosphorylation of adenosinetriphosphate. PC dephosphorylation varies linearly with the number of twitches and produces equivalent amounts of C1 and P1i.1 Iodoacetate concentrations which block the enzyme, creatine phosphokinase, render the muscle non-contractile. A value of 0.286 µmole/gm. for the amount of PC split per twitch is obtained which gives a value of -9.62 kcal./mole for the "physiological" heat of hydrolysis of PC in agreement with expectations based on thermochemical data. In a single maximal isometric twitch it is estimated that 2 to 3 PC molecules are dephosphorylated per myosin molecule, or 1 per actin molecule. The results support the view that under the conditions of these experiments PC dephosphorylation is the net energy yielding reaction. The in vivo stoichiometry of the mechano-chemistry of contraction revealed by these studies on the one hand, and the known stoichiometry of actin polymerization and its coupling to the creatine phosphokinase system on the other are strikingly similar and strongly suggest that the reversible polymerization of actin is involved in a major way in the contraction-relaxation-recovery cycle of muscle.