Meromyosin


Meromyosin is a part of myosin. With regards to human anatomy myosin and actin constitute the basic functional unit of a muscle fiber, called sarcomere, playing a role in muscle contraction.
Biochemically viewed meromyosin form subunits of the actin-associated motor protein, myosin, Following proteolysis, two types of meromyosin are formed: heavy meromyosin and light meromyosin.
Light meromyosin has a long, straight portion in the “tail” region. Heavy meromyosin is a protein chain terminating in a globular head portion/cross bridge. HMM consists of two subunits, Heavy Meromyosin Subunit 1 and 2. The majority of myosin activity is concentrated in HMMS-1. HMMS-1 has an actin binding site and ATP binding site that determines the rate of muscle contraction when muscle is stretched.
Light and heavy meromyosin are subunits of myosin filaments.