1) Superfamily of proteins that function as translocating proteins the common characteristics are to bind actin and hydrolyze MgATP generally consist of heavy chains which are involved in locomotion, and light chains which are are involved in regulation superfamily of myosins is organized into structural classes based upon the type and arrangement of the subunits they contain.

2) A fibrous globulin of muscle that can split ATP and that reacts with actin to form actomyosin.