Which of the following acts as competitively inhibiting enzyme responsible for synthesis of cholesterol

Options

A. Statins
B. Cyclosporin
C. Streptokinase
D. Lipases

Answer

**Step-by-Step Solution:**

1. **Understanding Competitive Inhibition:**
- Enzymes are biological catalysts that speed up chemical reactions in the body. They have an active site where substrates bind to undergo a reaction.
- Competitive inhibition occurs when an inhibitor, which has a similar structure to the substrate, competes with the substrate for binding to the enzyme's active site. If the inhibitor binds, the substrate cannot, preventing the reaction from occurring.

2. **Identifying the Options:**
- The options given are:
- Statin
- Cyclosporin
- Streptokinase
- Lipases

3. **Analyzing Each Option:**
- **Statin:** This is a class of drugs that lower cholesterol levels in the blood by competitively inhibiting the enzyme responsible for cholesterol synthesis. It binds to the active site of the enzyme, preventing the substrate from binding.
- **Cyclosporin:** This is an immunosuppressant used to prevent organ transplant rejection. It does not act as a competitive inhibitor for cholesterol synthesis.
- **Streptokinase:** This is an enzyme used to dissolve blood clots. It does not inhibit cholesterol synthesis.
- **Lipases:** These are enzymes that break down fats, not involved in cholesterol synthesis.

4. **Conclusion:**
- Based on the analysis, **Statin** is the correct answer as it acts as a competitively inhibiting enzyme responsible for the synthesis of cholesterol.

**Final Answer:** Statin

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