Protein digesting enzyme is -

Options

A. Pepsin
B. Chymotrypsinogen
C. Trophoprotein
D. Amylase

Answer

**Step-by-Step Text Solution:**

1. **Identify the Type of Enzyme**: The question asks for a protein-digesting enzyme. These enzymes are specifically responsible for breaking down proteins into smaller peptides and amino acids.

2. **Recognize the Enzyme**: The primary enzyme responsible for protein digestion in the human body is called "pepsin."

3. **Location of Production**: Pepsin is produced in the stomach. It is secreted by the gastric glands in an inactive form known as pepsinogen.

4. **Activation of the Enzyme**: Pepsinogen is activated to pepsin in the acidic environment of the stomach (due to hydrochloric acid), allowing it to begin the digestion of proteins.

5. **Function of Pepsin**: Once activated, pepsin breaks down proteins into smaller peptides, which can then be further digested by other enzymes in the small intestine.

**Final Answer**: The protein-digesting enzyme is **pepsin**.

---