A globular protein occurringwidely in muscle tissue as anoxygen carrier. It comprises a singlepolypeptide chain and a haem group, which reversibly binds a moleculeof oxygen. This is only relinquishedat relatively low externaloxygen concentrations, e.g. duringstrenuous exercise when muscle oxygendemand outpaces supply fromthe blood. Myoglobin thus acts as anemergency oxygen store.
Myoglobin is purified by CM-cellulose chromatography and Sephadex G-50 followed by chromatography on Amberlite IRC-50 Type III or BioRex 70 (<400mesh). The crystalline product as a paste in saturated (NH4)2SO4 at pH 6.5-7.0 may be stored at 4o for at least 4years unchanged, but must not be kept in a freezer. [Anres & Atassi Biochemistry 12 942 1980, Edmundson Biochemical Preparations 12 41 1968.]
