Which can give both carbylamine test and cerric ammonium nitrate test?

Options

A. Asn-Gln
B. Lys-Gln
C. Asp-Lys
D. Lys-Ser

Answer

To solve the question of which dipeptide can give both the carbylamine test and the ceric ammonium nitrate test, we need to analyze the functional groups present in each dipeptide option provided.

### Step-by-Step Solution:

1. **Understand the Tests**:
- **Carbylamine Test**: This test is positive for primary amines. When a primary amine reacts with chloroform and a strong base, it produces an isocyanide, which has a characteristic foul odor.
- **Ceric Ammonium Nitrate (CAN) Test**: This test is positive for alcohols. It indicates the presence of hydroxyl (-OH) groups, which react with ceric ammonium nitrate to form a colored complex.

2. **Identify the Dipeptides**:
The options given are:
- Option 1: Asparagine-Glutamine (ASN-GLN)
- Option 2: Lysine-Glutamine (LYSN-GLN)
- Option 3: Aspartic Acid-Lysine
- Option 4: Lysine-Serine

3. **Draw Structures and Identify Functional Groups**:
- **Asparagine-Glutamine**: Contains an amine group (NH2) but no hydroxyl group (OH).
- **Lysine-Glutamine**: Contains an amine group (NH2) but no hydroxyl group (OH).
- **Aspartic Acid-Lysine**: Contains an amine group (NH2) and a carboxylic acid (COOH) but no hydroxyl group (OH).
- **Lysine-Serine**: Contains an amine group (NH2) and a hydroxyl group (OH).

4. **Analyze Each Dipeptide**:
- **Asparagine-Glutamine**: Positive for carbylamine test, negative for CAN test (no OH).
- **Lysine-Glutamine**: Positive for carbylamine test, negative for CAN test (no OH).
- **Aspartic Acid-Lysine**: Positive for carbylamine test, negative for CAN test (no OH).
- **Lysine-Serine**: Positive for both carbylamine test (NH2) and CAN test (OH).

5. **Conclusion**:
The only dipeptide that can give both the carbylamine test and the ceric ammonium nitrate test is **Lysine-Serine**.

### Final Answer:
**Lysine-Serine (Option 4)** can give both the carbylamine test and the ceric ammonium nitrate test.