Myoglobin is a compact globular protein consisting of just 153 amino acids. It is known to have the tertiary structure of protein as it is made up of 1 subunit. The single polypeptide is found in muscles and provides vital stores of oxygen to the muscle cells when required e.g. this is particluarly advantageous for diving mammals whom have significant amounts of myoglobin in their muscles. When the tissue concentration is normal, myoglobin is highly saturated with oxygen but it has low oxygen saturation at low tissue concentrations. Myoglobin, like haemoglobin, has a haem group which contains iron and binds to oxygen. However, the binding affinity to oxygen is higher than haemoglobin. This iron in the haem group gives muscle its red colour. The alpha helical 3D structure of the protein was one of the first to be discovered by John Kendrew who studied myoglobin in sperm whales using x-ray crystallography.
- ↑ Berg J M, Tymoczko J L, Gatto Jr. G J and Stryer L, Biochemistry. 8th Edition, Chapter 7: 196, New York: W.H Freeman and Company, Kate Ahr Parker, 2015.