to which structure would tropomyosin and troponin be associated with
Tropomyosin and Troponin Tropomyosin and troponin are two other proteins found in small quantities in muscle. They help regulate muscle contraction. Troponin is associated with the thin filaments and can bind to the actin molecules. There is usually one troponin per 6-8 actin molecules. Tropomyosin is a long thin protein that extends between, and binds to, the troponin molecules. When troponin is bound to actin, the tropomyosin is positioned so it prevents the myosin heads from contacting actin, thus preventing contraction.