tro-PO-nin A type of protein in thin myofilaments of skeletal muscle cells. 695
A complex of globular calcium-binding proteins associated with actin and tropomyosin in the thin filaments of muscle. When troponin binds calcium, it undergoes a conformational change, allowing tropomyosin to reveal myosin-binding sites on the actin filament.
A type of protein that helps muscles contract (work). Different forms of troponin are found in different muscles in the body. The types found in the heart are specific to heart muscle and make good cardiac markers.
Muscle protein binding actin and tropomyosin; when calcium is present, it 'pulls' tropomyosin to uncover binding sites for myosin.
Troponin is a complex of three proteins that is integral to muscle contraction in skeletal and cardiac muscle, but not smooth muscle. Troponin is attached to the protein tropomyosin and lies within the groove between actin filaments in muscle tissue. In a relaxed muscle, tropomyosin blocks the attachment site for the myosin crossbridge, thus preventing contraction.
