Megerman J, Lowey S
Biochemistry. 1981 Apr 14;20(8):2099-110. doi: 10.1021/bi00511a006.
Myosin from smooth muscle of the calf aorta has been found to be similar to rabbit skeletal muscle myosin in molecular weight, sedimentation coefficient, and amino acid composition. When dialyzed at low ionic strength, it also forms polymers that exist in equilibrium with the "monomer", the position of this equilibrium being sensitive to ionic strength, pH, and hydrostatic pressure. The self-association reactions for smooth muscle myosin differ, however, from those observed for skeletal muscle myosin in several ways: (1) aorta myosin polymerizes at a higher ionic strength to form a smaller polymer; (2) between pH 6 and 8, only one polymer boundary is observed; (3) the result of varying total protein concentration on the myosin-polymer equilibrium cannot be analyzed by the Gilbert theory for a simple two-species system, as was possible with skeletal myosin. This more complex polymerization behavior may be related to differences in the mode of assembly between smooth and skeletal muscle myosin.
已发现小牛主动脉平滑肌中的肌球蛋白在分子量、沉降系数和氨基酸组成方面与兔骨骼肌肌球蛋白相似。在低离子强度下透析时，它也会形成聚合物，这些聚合物与“单体”处于平衡状态，该平衡的位置对离子强度、pH值和静水压力敏感。然而，平滑肌肌球蛋白的自缔合反应在几个方面与骨骼肌肌球蛋白的自缔合反应不同：（1）主动脉肌球蛋白在较高离子强度下聚合形成较小的聚合物；（2）在pH 6至8之间，仅观察到一个聚合物边界；（3）改变总蛋白浓度对肌球蛋白-聚合物平衡的影响无法用吉尔伯特理论对简单的双物种系统进行分析，而骨骼肌肌球蛋白则可以。这种更复杂的聚合行为可能与平滑肌和骨骼肌肌球蛋白组装模式的差异有关。
