肌球蛋白是一种主要的收缩蛋白，它通过 ATP 的水解将化学能转化为机械能。肌球蛋白是由一对肌球蛋白重链 (MYH) 和两对不同的轻链组成的六聚体蛋白质。肌球蛋白重链由多基因家族编码。在哺乳动物中，至少有 10 种不同的肌球蛋白重链 (MYH) 异构体已被描述为来自横纹细胞、平滑细胞和非肌肉细胞。这些亚型显示在发育过程中在空间和时间上受到调节的表达。[RefSeq 提供，2008 年 7 月]

Myosin is a major contractile protein which converts chemical energy into mechanical energy through the hydrolysis of ATP. Myosin is a hexameric protein composed of a pair of Myosin heavy chains (MYH) and two pairs of nonidentical LIGHT chains. Myosin heavy chains are encoded by a multigene family. In mammals at least 10 different Myosin heavy chain (MYH) isoforms have been described from striated, smooth, and nonmuscle cells. These isoforms show expression that is spatially and temporally regulated during development. [provided by RefSeq, Jul 2008]