[ak-tuh
n] 
| a globulin that is present in muscle plasma and that in connection with myosin plays an important role in muscle contraction. |
| var. of actino- before a vowel: actinism. |
| a combining form with the meaning “ray, beam,” used in the formation of compound words, with the particular senses “radiation” in the physical sciences (actinometer) and “having raylike structures,” “radiate in form” in biology (actinomyces; actinopod). |
| ac·tin (āk'tĭn) n. A protein found in muscle that together with myosin functions in muscle contraction. [Latin āctus, motion; see act + -in.] |
actin ac·tin (āk'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.
actino- or actin-
pref.
Actinic radiation: actinotherapy.
| actin (āk'tĭn) Pronunciation Key
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. |
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