The peptide that gives positive ceric ammonimum nitrate and carbylamine tests is:

Options

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

Answer

To determine the peptide that gives positive ceric ammonium nitrate and carbylamine tests, we need to analyze the functional groups present in the given peptides.

### Step-by-Step Solution:

1. **Understanding the Tests:**
- **Ceric Ammonium Nitrate Test:** This test is positive for compounds containing alcohol (-OH) or phenolic groups.
- **Carbylamine Test:** This test is positive for primary amines (1° amines), which have the structure -NH2.

2. **Analyzing the Peptides:**
- **Option A: Serine (Ser)**
- Functional Group: Serine has a hydroxyl group (-OH) which makes it capable of giving a positive ceric ammonium nitrate test.
- **Option B: Lysine (Lys)**
- Functional Group: Lysine has an amino group (-NH2), which qualifies it as a primary amine. Therefore, it can give a positive carbylamine test.
- **Option C: Glutamine (Gln)**
- Functional Group: Glutamine has an amide group (C=O, NH2) and does not have a primary amine that would give a positive carbylamine test.
- **Option D: Aspartic Acid (Asp)**
- Functional Group: Aspartic acid has a carboxylic acid group (-COOH) and does not contain a primary amine, thus it cannot give a positive carbylamine test.

3. **Conclusion:**
- Since Serine gives a positive ceric ammonium nitrate test and Lysine gives a positive carbylamine test, the peptide that gives both tests is **Lysine** (Option A).

### Final Answer:
The peptide that gives positive ceric ammonium nitrate and carbylamine tests is **Lysine (Option A)**.