The proteolytic enzyme that acts first on proteins in the proçés of digestion is

Options

A. ptyalin
B. pepsin
C. trypsin
D. chymotrypsin

Answer

To solve the question "The proteolytic enzyme that acts first on proteins in the process of digestion is," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for the first proteolytic enzyme that acts on proteins during digestion.

2. **Identify the Digestion Process**: Digestion begins in the mouth (buccal cavity) where carbohydrates are primarily digested by salivary amylase. However, we are interested in protein digestion.

3. **Locate the Site of Protein Digestion**: Protein digestion primarily starts in the stomach.

4. **Identify the Enzymes Involved**: In the stomach, the gastric glands secrete pepsinogen, which is an inactive form of the enzyme pepsin.

5. **Activation of Pepsin**: Hydrochloric acid (HCl) present in the stomach converts pepsinogen into its active form, pepsin.

6. **Function of Pepsin**: Pepsin is a proteolytic enzyme that begins the process of protein digestion by breaking down proteins into smaller peptides.

7. **Consider Other Options**:
- **Tylenol** (likely a confusion with salivary amylase) acts on carbohydrates, not proteins.
- **Trypsin** and **Chymotrypsin** are produced in the pancreas and act later in the digestive process, after pepsin.

8. **Conclusion**: Since pepsin is the first enzyme that acts on proteins during digestion, the answer to the question is **B - Pepsin**.

### Final Answer:
The proteolytic enzyme that acts first on proteins in the process of digestion is **B - Pepsin**.

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