Which of the following protein prevents contraction by covering binding sites on actin tereby preventing its interaction with myosin?: (A) Thymosin, (B) Troponin, (C) Calmodulin, (D) Tropomyosin
Answer is D. Tropomyosin molecules lie on top of the active sites of the actin strands, thereby preventing the attraction between the actin and myosin filaments. Ref: Review of Medical Physiology, 23rd Edition By Wiiliam F Ganong; Guyton and Hall Medical Physiology, 10th Edition, Page 71.