Myosin is one of the two major proteins responsible for contraction of muscles. It is composed of two twisted protein strands with projecting parts called cross-bridges. It contains two heavy chains part of a heavy chain makes up one head and the other part forms the tail. Many of these strands together form a myosin filament. These globular portions of the myosin filaments contain an enzyme called ATPase, which catalyzes the breakdown of ATP, releasing energy that puts the myosin cross-bridges in a cocked position. The sliding filament theory of muscle contraction states that the head of myosin cross-bridges can attach to an actin binding site and bend slightly, pulling the actin filaments with it. So, myosin and actin help muscle to produce movement.
1 Answer November 6, 2018