[ mahy-uh-sin ]
/ ˈmaɪ ə sɪn /

noun Biochemistry.

the principal contractile protein of muscle.



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Origin of myosin

First recorded in 1865–70; my- + -ose2 + -in2 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Example sentences from the Web for myosin

  • Into this special class fall myosin (of the muscles), fibrinogen (of the blood) and vitellin (of egg yolk).

    Animal Proteins|Hugh Garner Bennett
  • The pemmican we used consisted of powdered dried beef (containing the important protein, myosin) and 50 per cent.

  • Another similar experiment made with antipeptone, formed from the myosin of muscle-tissue, gave like results.

    On Digestive Proteolysis|R. H. Chittenden
  • Other forms of protein are globulin and myosin, which form the actual muscle-substance.

    Encyclopedia of Diet|Eugene Christian

British Dictionary definitions for myosin

/ (ˈmaɪəsɪn) /


the chief protein of muscle that interacts with actin to form actomyosin during muscle contraction; it is also present in many other cell types

Word Origin for myosin

C19: from myo- + -ose ² + -in
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for myosin

[ mīə-sĭn ]


The commonest protein in muscle cells, a globulin responsible for the elastic and contractile properties of muscle and combining with actin to form actomyosin.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Scientific definitions for myosin

[ mīə-sĭn ]

A protein found in muscle tissue as a thick filament made up of an aggregate of similar proteins. Myosin and the protein actin form the contractile units (sarcomeres) of skeletal muscle. In the sarcomere, actin and myosin filaments slide past each other to cause the shortening of a muscle fiber.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.