Muscle proteins and their functions:
- Actin: Actin is a thin filament protein that is involved in muscle contraction. It provides the framework upon which the myosin filaments slide during muscle contraction. Actin does not possess ATPase activity.
- Troponin: Troponin is a regulatory protein that is involved in muscle contraction. It helps to control the interaction between actin and myosin by binding to calcium ions. Troponin does not possess ATPase activity.
- Myosin: Myosin is a thick filament protein that is primarily responsible for muscle contraction. It possesses ATPase activity, which allows it to hydrolyze ATP and convert the energy released into mechanical work. This ATPase activity is crucial for the sliding of actin and myosin filaments during muscle contraction.
- Tropomyosin: Tropomyosin is another regulatory protein that is involved in muscle contraction. It helps to block the binding sites on actin, preventing the interaction with myosin in the absence of calcium ions. Tropomyosin does not possess ATPase activity.
Conclusion:
The muscle protein that acts as ATPase is myosin. It possesses ATPase activity, allowing it to hydrolyze ATP and provide the necessary energy for muscle contraction.