In: Biology
What is Hemoglobin, its structure, function, normal levels and the types of hemoglobin in humans?
Hemoglobin:
It is a type of globular protein present in RBC that transports oxygen in our body through blood.
Structure:
In 1959, the molecular structure of hemoglobin was described by Max Perutz.
It is a tetrameric protein.
The main type of hemoglobin in adults is made up of 2 subunits - α and β.
Each polypeptide is linked to a heme prosthetic group.
α - subunit is made up of alpha polypeptide chains having 141 amino acid residues.
β - subunit is made up of beta polypeptide chains having 146 amino acid residues.
Heme group: It is an iron containing prosthetic group which is attached to each polypeptide chain.
Normal levels:
Age group | Hemoglobin count (gm/dl) |
1. New born babies | 17-22 |
2. Children | 11-13 |
3. Adults (Ma)le | 14-18 |
4. Adults (Female) | 12-16 |
5. Elderly (Male) | 12.4-14.9 |
6. Elderly (Female) | 11.7-13.8 |
Types of Hemoglobin:
Embryonic hemoglobin:
1. Hemoglobin Gower I - The 4 polypeptide chains that compose this type of Hb are 2 zeta and 2 epsilon chains.
2. Hemoglobin Gower II - Composed of 2 alpha and 2 epsilon chains.
3. Hemoglobin Portland I - Composed of 2 zeta and 2 gamma polypeptides chains.
4. Hemoglobin Portland II - Composed of 2 zeta and 2 beta polypeptide chains.
Adult Hemoglobin:
Hemoglobin:
Hemoglobin is defined as the protein molecule in red blood cells which carries oxygen from the lungs to the body's tissues and returns carbon dioxide from the tissues back to the lungs.