The prosthetic group of haemoglobin is

Options

A. Porphin
B. Haem
C. Globin
D. Globulin

Explanation

To solve the question regarding the prosthetic group of hemoglobin, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Hemoglobin**: Hemoglobin is a protein found in red blood cells that is responsible for transporting oxygen throughout the body. It consists of globin (the protein part) and heme (the non-protein part).

2. **Identifying the Prosthetic Group**: A prosthetic group is a non-polypeptide unit that is tightly and permanently attached to a protein and is essential for the biological activity of that protein. In the case of hemoglobin, the prosthetic group is known as heme.

3. **Composition of Heme**: The heme group contains an iron atom (Fe) that is crucial for binding oxygen. The iron in heme is in the ferrous state (Fe²⁺), which allows it to bind to oxygen molecules.

4. **Structure of Heme**: Heme is composed of a porphyrin ring structure, specifically a protoporphyrin, which consists of four pyrrole rings connected by methine bridges. This structure is what holds the iron atom in place.

5. **Conclusion**: Therefore, the prosthetic group of hemoglobin is heme, which includes the iron atom in the ferrous state (Fe²⁺) and is located within the porphyrin structure.

### Final Answer:
The prosthetic group of hemoglobin is **heme** (Fe²⁺).

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