Which of the following contain disulphide linkages?

Options

A. Oxytocin
B. Vasopressin
C. Insulin
D. Haemoglobin

Answer

To determine which of the given options contain disulfide linkages, we need to analyze each option based on their structure and the presence of disulfide bonds.

### Step-by-Step Solution:

1. **Understanding Disulfide Linkages**:
- Disulfide linkages (or bonds) are covalent bonds formed between two sulfur atoms, typically from the thiol (-SH) groups of cysteine residues in proteins. They play a crucial role in stabilizing the three-dimensional structure of proteins.

2. **Analyzing Each Option**:
- **Oxytocin**:
- Oxytocin is a peptide hormone composed of nine amino acids. It contains a disulfide bond between two cysteine residues, which is essential for its structural stability.
- **Vasopressin**:
- Vasopressin, also known as antidiuretic hormone (ADH), is another peptide hormone with a similar structure to oxytocin. It also contains a disulfide bond between two cysteine residues.
- **Insulin**:
- Insulin is a peptide hormone that consists of two chains (A and B) linked by disulfide bonds. It has three disulfide bonds in total, contributing to its functional structure.
- **Hemoglobin**:
- Hemoglobin is a protein responsible for oxygen transport in the blood. It consists of four polypeptide chains (two alpha and two beta chains) and does not contain disulfide bonds in its structure.

3. **Conclusion**:
- Based on the analysis, both oxytocin and vasopressin contain disulfide linkages. Insulin also contains disulfide linkages. Hemoglobin does not contain disulfide linkages.
- Therefore, the correct options that contain disulfide linkages are: **Oxytocin, Vasopressin, and Insulin**.

### Final Answer:
- The options that contain disulfide linkages are **Oxytocin, Vasopressin, and Insulin**.