myosin

myosin

 [mi´o-sin]

one of the two main proteins of muscle. Myosin and actin are the proteins involved in contraction of muscle fibers.

my·o·sin

(mī'ō-sin),

A globular protein present in muscle and in nonmuscle cells that has an ATPase activity; in combination with actin, it forms actomyosin; myosin forms the thick filaments in muscle.

myosin

/my·o·sin/ (mi´o-sin) a protein of the myofibril, occurring chiefly in the A band; with actin it forms actomyosin, which is responsible for the contractile properties of muscle.

myosin

(mī′ə-sĭn)

n.

Any of a class of proteins that bind with actin filaments and generate many kinds of cell movement, especially the contraction of myofibrils in muscle cells.

myosin

[mī′əsin]

Etymology: Gk, mys + in, within

a protein that makes up close to one half of the total protein in muscle tissue. The interaction between myosin and another protein, actin, is essential for muscle contraction. See also actino-.

my·o·sin

(mī'ō-sin)

A globulin present in muscle; in combination with actin, it forms actomyosin; myosin forms the thick filaments in muscle.

myosin

a protein found in the thick filaments of the SARCOMERES OF MUSCLE. Myosin combines with ACTIN to produce ACTOMYOSIN during contraction.

myosin

one of the two main myofibrillar proteins in the myofibrils of a muscle fibre. A dimeric molecule comprising two identical monomers. Each monomer consists of a long chain ('light meromyosin, LMM') which readily associates with the chains of other myosin molecules to form the thick filaments, and a more globular component ('heavy meromyosin, HMM'), itself further divisible into two subunits, S2 and S1. The latter are the myosin head-groups, embodying an ATPase and an actin-binding site; it is these that interact with actin in the thin filaments when the muscle is activated, to form the force-generating (actin-myosin) cross-bridges. This whole monomer constitutes one myosin heavy chain (MHC). However, associated with the head-groups are two myosin light chains (MLC), of uncertain function. (Since myosin is not the only constituent of thick filaments, the term 'myosin filament' is a misnomer and better avoided). See also muscle contraction, sliding filament theory.

myosin

muscle globulin; forms actomyosin with actin

myosin,

n one of the two proteins responsible for muscle contraction, the other protein being actin. Contraction occurs when the two protein bundles slide over one another. See also actin.

my·o·sin

(mī'ō-sin)

A globulin present in muscle; in combination with actin, it forms actomyosin.

myosin

(mī´əsin´),
n a cardiac and skeletal muscle protein that makes up close to one half of the proteins that occur in muscle tissue. The interaction of myosin and actin is essential for muscle contraction.

myosin

one of the two main proteins of muscle. Myosin and actin are the proteins involved in contraction of muscle fibers.

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myosin ATPase

catalyzes the physicochemical interactions of actin and myosin during muscle contraction.

myosin light chains

each molecule of smooth muscle cell myosin contains two pairs of light molecular weight chains (MLCs), one alkali MLC and one regulatory MLC.