actin

[ak-tuh n]

noun Biochemistry.

a globulin that is present in muscle plasma and that in connection with myosin plays an important role in muscle contraction.

Origin of actin

1940–45; perhaps act + -in²

actin-

variant of actino- before a vowel: actinism.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for actin

Historical Examples of actin

"The mare's actin' as if she'd a cup of tea, too," muttered her companion, Ned.
Thoroughbreds
W. A. Fraser
The nigher we got, the harder he stared; and the man in front was actin' similar in regards to him.
The Depot Master
Joseph C. Lincoln
And yet, if she wanted Jonadab, she was actin' mighty funny.
The Depot Master
Joseph C. Lincoln
All I should be able to think of was what she wore, or didn't wear, when she was actin' her parts.
Kent Knowles: Quahaug
Joseph C. Lincoln
Your Uncle Zoeth and me have been actin' as your pilots for a consider'ble spell.
Mary-'Gusta
Joseph C. Lincoln

British Dictionary definitions for actin

actin

noun

a protein that participates in many kinds of cell movement, including muscle contraction, during which it interacts with filaments of a second protein, myosin

Word Origin for actin

C20: from act + -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

Medicine definitions for actin

actin

[ăk′tĭn]

n.

One of the protein components found in muscle, existing as F-actin or G-actin, into which actomyosin can be split and which acts with myosin in muscle contraction.

Science definitions for actin

actin

[ăk′tĭn]

A protein found in all eukaryotic cells, forming filaments that make up a main component of the cell's supporting matrix or cytoskeleton. Actin and the protein myosin together make up the contractile units (called sarcomeres) of skeletal muscle fibers.