Which of the following amino acids contains sulphur in its structure

Options

A. Proline
B. Cysteine
C. Leucine
D. Histidine

Explanation

To determine which of the following amino acids contains sulfur in its structure, we will analyze each option one by one.

### Step 1: Analyze Proline
- Proline is an amino acid that has a unique cyclic structure.
- Its structure can be represented as follows:
- **Structure**:
- It has an amine group (-NH2) and a carboxylic acid group (-COOH).
- Proline does not contain sulfur in its structure.

### Step 2: Analyze Cysteine
- Cysteine is known for containing a thiol group (-SH), which is where the sulfur is found.
- Its structure can be represented as follows:
- **Structure**:
- NH2-CH(COOH)-SH
- Cysteine contains a sulfur atom in its structure.

### Step 3: Analyze Leucine
- Leucine is a branched-chain amino acid.
- Its structure can be represented as follows:
- **Structure**:
- NH2-CH(CH3)-CH2-COOH
- Leucine does not contain sulfur in its structure.

### Step 4: Analyze Histidine
- Histidine is an amino acid that contains an imidazole side chain.
- Its structure can be represented as follows:
- **Structure**:
- NH2-CH(COOH)-C3H3N
- Histidine does not contain sulfur in its structure.

### Conclusion
After analyzing all four amino acids, we find that only **cysteine** contains a sulfur atom in its structure. Therefore, the correct answer is:

**Cysteine**.

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