Muscle fiber protein that normally inhibits muscle contraction. Following nerve stimulation, calcium binds to troponin, blocking its inhibitory effect; normal contraction then occurs. Troponin is often released following myocardial infarction (heart attack). Its presence in the blood may be helpful in early diagnosis and treatment.
An inhibitory protein in muscle fibers. The action potential at the sarcolemma causes. the sarcoplasmic reticulum to release calcium ions, which bond to troponin and shift tropomyosin away from the myosinbinding sites of actin, permitting contraction.