Volume changes in isolated myofibrils

Biochimica et Biophysica Acta (BBA) - Specialized Section on Biophysical Subjects Pub Date : 1964-11-29 DOI:10.1016/0926-6577(64)90095-6

R.J. Baskin

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引用次数: 5

Abstract

Volume changes in glycerol-extracted myofibrils were studied. The effect of pH, ion content and ATP concentration on the change in volume was determined. A volume change greater than that attributed to ATP dephosphorylation was observed. The magnitude of the volume change of the entire system was 10⁻³ cm³ whereas that due to dephosphorylation was 10⁻⁶ cm³. The ratio of ATPase activity in a volume decrease to that in a volume increase was found to be approx. 10:1. The total amount of volume decrease measured approx. 0.028 cm³/g of muscle with a fresh myo fibril preparation. The volume increase which was observed upon the addition of large amounts of ATP amounted to approx. 0.036 cm³/g of muscle. The relationship between the volume changes and molecular reorganization of the myofibril proteins was discussed. It was concluded that either a large configurational change occurs in the myofibril proteins during an ATP-induced contraction or relaxation, or that the volume changes are related to the dissociation and association of actin and myosin filaments

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离体肌原纤维的体积变化

研究了甘油提取肌原纤维的体积变化。测定了pH、离子含量和ATP浓度对体积变化的影响。观察到比ATP去磷酸化更大的体积变化。整个体系的体积变化幅度为10−3 cm3，而由于去磷酸化导致的体积变化幅度为10−6 cm3。体积减小时的atp酶活性与体积增大时的atp酶活性之比接近。10:1。测量到的体积减少总量约为。0.028 cm3/g的肌肉，用新鲜的肌原纤维制备。在加入大量ATP后观察到的体积增加约为。0.036 cm3/g肌肉。讨论了肌原纤维蛋白的体积变化与分子重组的关系。结论是，在atp诱导的收缩或松弛过程中，肌原纤维蛋白发生了大的结构变化，或者体积变化与肌动蛋白和肌球蛋白丝的解离和结合有关

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Biochimica et Biophysica Acta (BBA) - Specialized Section on Biophysical Subjects

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