Which of the following acts in acidic medium ?

Options

A. Trypsin
B. Pepsin
C. Amylase
D. Lipase

Answer

To determine which enzyme acts in an acidic medium, we can analyze the given options step by step:

### Step-by-Step Solution:

1. **Identify the Enzymes**: The options provided are trypsin, pepsin, amylase, and lipase.

2. **Understand the Function of Each Enzyme**:
- **Trypsin**: This enzyme is involved in protein digestion and is active in the small intestine, where the pH is more alkaline (basic).
- **Amylase**: This enzyme helps in the digestion of carbohydrates and is found in saliva and the small intestine, both of which are also in a more basic environment.
- **Lipase**: This enzyme is responsible for the digestion of fats and operates in the small intestine, where the pH is neutral to slightly basic.

3. **Focus on Pepsin**:
- **Pepsin**: This enzyme is specifically designed to function in the acidic environment of the stomach. It is secreted as an inactive precursor called pepsinogen, which is activated by hydrochloric acid (HCl) in the stomach. The acidic pH (around 1.5 to 3.5) is essential for its activity.

4. **Conclusion**: Among the options, pepsin is the only enzyme that operates in an acidic medium. Therefore, the answer is **pepsin**.

### Final Answer:
Pepsin acts in an acidic medium.

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