actin definition by Webster's New World
a protein in muscles
Origin: ; from Classical Latin actus (see act) plush -in
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
actino-: used before a vowel: actinal
actin definition by American Heritage Dictionary
A protein found in muscle that together with myosin functions in muscle contraction.
Origin: Latin āctus, motion; see act + -in.
prefixThe American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Variant of actino-.
actin - Medical Definition
The American Heritage® Medical Dictionary Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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.
actin - Science Definition
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.