troponin

views updated May 21 2018

troponin A complex of three polypeptide chains that are found at regular intervals along the length of an actin filament. During muscle contraction, troponin binds to calcium ions, displacing tropomyosin and exposing the binding site on the actin filament. This allows the interaction of actin and myosin to occur. See sliding filament theory.

troponin

views updated May 18 2018

troponin A globular protein associated in vivo with actin and tropomyosin in the thin filaments of striate muscle.

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