Fazekas S, Székessy-Hermann V
Orv Hetil. 1989 Aug 6;130(32):1707-10, 1713.
Studying the mechanism of muscular contraction not even in one of the cases deriving from 50 sources could be obtained a myosin preparation free of phosphate. Therefore the aim of the authors was to elaborate methods which provided means for producing preparations of an endogenous P content that approached the P content of myosins of live sources. The phosphoryl groups of myosin may be released by incubating these preparations with F-actin. The actin attaches to the interaction domain of myosin and upon its effect P migrates within the myosin molecule from the site of phosphorylation to the interaction domain. At the interaction the myosin attaches to the actin through the phosphoryl group subsequently the myosin head turns from 90 degrees to 45 degrees consequently the actin-filament moves to a 12 mm distance towards the center of the sarcomer. When the myosin-actin-phosphoryl bridge ceases to be the P attaches transiently to the actin and the anorganic phosphate releases from the actin. The active center of myosin is filled again with the gamma phosphoryl group of ATP and the head returns simultaneously to the resting position of 90 degrees.
研究肌肉收缩机制时，即使从50种来源的样本中，也无法获得不含磷酸盐的肌球蛋白制剂。因此，作者的目标是完善方法，以提供制备内源性磷含量接近活体来源肌球蛋白磷含量的制剂的手段。肌球蛋白的磷酸基团可通过将这些制剂与F-肌动蛋白孵育而释放。肌动蛋白附着于肌球蛋白的相互作用结构域，在其作用下，磷在肌球蛋白分子内从磷酸化位点迁移至相互作用结构域。在相互作用时，肌球蛋白通过磷酸基团附着于肌动蛋白，随后肌球蛋白头部从90度旋转至45度，结果肌动蛋白丝向肌节中心移动12毫米。当肌球蛋白-肌动蛋白-磷酸桥不再存在时，磷短暂附着于肌动蛋白，无机磷酸盐从肌动蛋白释放。肌球蛋白的活性中心再次被ATP的γ磷酸基团填充，同时头部回到90度的静止位置。
