Haemoglobin
Haemoglobin (also hemoglobin, or abbreviated Hb) is a protein which used in red blood cells to store and transport oxygen.
Haemoglobin is made up of four polypeptide subunits, two alpha (α) subunits and two beta (β) subunits. Each of the four subunits contains a heme molecule, where the oxygen itself is bound through a reversible reaction, meaning that a haemoglobin molecule can transport four oxygen molecules at a time.
The reversible nature of the binding of oxygen allows for both the uptake of oxygen in the lungs and its release in body tissues.
The heme molecules each contain a single central iron atom and are responsible for giving the red colour to haemoglobin, and thus to the blood as a whole. [1]
References
- ↑ Alberts B, Bray D, Hopkin K, Johnson A, Lewis J, Raff M, Roberts K and Walter P (2010) Essential Cell Biology, 3rd Edition, New York: Garland Science