myosin

myosin
A globulin present in muscle that has an ATPase activity; in combination with actin, it forms actomyosin; m. forms the thick filaments in muscle.
- m. light chain kinase a calcium/calmodulin-dependent enzyme that phosphorylates the light chains of smooth muscle m. and initiates contraction. In skeletal muscle, phosphorylation modulates tension during contraction.

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my·o·sin 'mī-ə-sən n
1) ACTOMYOSIN
2) a fibrous globulin of muscle that can split ATP and that reacts with actin to form actomyosin

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n.
the most abundant protein in muscle fibrils, having the important properties of elasticity and contractility. With actin, it comprises the principal contractile element of muscles. See striated muscle.

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my·o·sin (miґo-sin) any of a family of proteins with ATPase activity, existing in a number of isoforms; it moves along actin filaments (F-actin) using the energy from ATP hydrolysis. Myosin consists of a head that produces motion by “walking” along the actin filament and is joined by a neck domain to a tail that contains binding sites determining specific activity. Within cells, myosins are involved in transport of vesicles and organelles. Myosin II, made up of two heavy and four light chains, is the main constituent of the thick filaments of muscle fibers, is responsible for the contraction and relaxation of muscle, and is the motor that drives cytokinesis. Cf. actomyosin. See Plate 32.

Medical dictionary. 2011.

Look at other dictionaries:

  • Myosin — bezeichnet eine Familie von Motorproteinen in eukaryotischen Zellen. Myosin ist als ein wesentlicher Bestandteil im Muskel auch an der Umwandlung von chemischer Energie in Kraft und Bewegung beteiligt. Des Weiteren ist es in Kooperation mit… …   Deutsch Wikipedia

  • Myosin II — ist ein dimeres Motorprotein in eukaryotischen Zellen. Es kommt im Sarkomer der Skelettmuskulatur vor und ist unabdingbar für die Muskelkontraktion. Aufbau Myosin II besteht aus 6 Untereinheiten, 2 schweren und 4 leichten Ketten. Es hat eine… …   Deutsch Wikipedia

  • Myosin — Myosin, in vielen pflanzlichen und tierischen Zellen, v.a. in Muskelzellen, vorhandenes Protein, das zusammen mit ⇒ Actin Bewegungsvorgänge ermöglicht. Molekulares M. besteht aus sechs Untereinheiten, zwei identischen schweren und vier leichten… …   Deutsch wörterbuch der biologie

  • Myosin — My o*sin, n. [Gr. my^s, myo s a muscle.] (Physiol. Chem.) A protein present in muscle, serving as the principle contractile protein in muscle contraction. Note: It was earlier considered as being formed in the process of coagulation which takes… …   The Collaborative International Dictionary of English

  • myosin — myosin. См. миозин. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • Myosīn — Myosīn, s. Muskeleiweißkörper …   Meyers Großes Konversations-Lexikon

  • Myosin — Myosīn, s. Fibrin und Globuline …   Kleines Konversations-Lexikon

  • myosin — [mī′ō sin] [< Gr mys (gen. myos), a muscle, MOUSE + IN1] n. a protein in muscles: see ACTOMYOSIN …   English World dictionary

  • Myosin — Part of the myosin II structure. Atoms in the heavy chain are colored red on the left hand side, and atoms in the light chains are colored orange and yellow. Myosins comprise a family of ATP dependent motor proteins and are best known for their… …   Wikipedia

  • myosin — A family of motor ATPases that interact with F actin filaments. An increasing number of different myosins are being described. Classical striated muscle myosin is myosin II. (See also myosin light chains, meromyosin.) Myosin I is a low molecular… …   Dictionary of molecular biology

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