Contractile protein of skeletal muscle involing ATPase activity is :

Options

A. Troponin
B. Tropomyosin
C. `alpha`-actinin
D. Myosin

Answer

To solve the question regarding the contractile protein of skeletal muscle that involves ATPase activity, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: We need to identify which protein among the given options has ATPase activity and is involved in muscle contraction.

2. **Analyzing the Options**:
- **Troponin**: This is a regulatory protein that binds to calcium and helps in muscle contraction but does not have ATPase activity.
- **Tropomyosin**: This protein also plays a role in muscle contraction by stabilizing actin filaments but does not have ATPase activity.
- **Alpha-actinine**: This protein is involved in anchoring actin filaments in the sarcomere but does not exhibit ATPase activity.
- **Myosin**: This is a contractile protein that is known for its ATPase activity, which is crucial for muscle contraction.

3. **Identifying the Correct Answer**: Among the options, myosin is the only protein that has ATPase activity and is essential for muscle contraction.

4. **Conclusion**: Therefore, the correct answer to the question is **D. Myosin**.