Which of the following is a protein

Options

A. Pepsin
B. Adrenaline
C. ATP
D. Glutamine

Explanation

To determine which of the following options is a protein, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Identify the Options**: First, we need to know the options given in the question. In this case, we have:
- Option 1: Pepsin
- Option 2: Adrenaline
- Option 3: Glutamine
- Option 4: ATP

2. **Analyze Each Option**:
- **Option 1: Pepsin**: Pepsin is a digestive enzyme that breaks down proteins into smaller peptides. It is indeed a protein itself, classified as a protease.
- **Option 2: Adrenaline**: Adrenaline (also known as epinephrine) is a hormone produced by the adrenal glands. It is not a protein; it is classified as a catecholamine.
- **Option 3: Glutamine**: Glutamine is an amino acid, which is a building block of proteins. However, it is not a protein itself.
- **Option 4: ATP (Adenosine Triphosphate)**: ATP is a nucleotide that serves as a primary energy carrier in cells. It is not a protein.

3. **Conclusion**: Based on the analysis, the only option that qualifies as a protein is **Pepsin**.

### Final Answer:
The correct answer is **Pepsin**.

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