Hæmoglobin and Myoglobin: Cooperativity

Abstract

Myoglobin is a protein with a single haeme group, which binds oxygen inside our cells and makes it available for metabolism. Oxygen binding to myoglobin is described by a hyperbola. Haemoglobin consists of two ',"-protomers, each of the four proteins contains a haeme group. Binding of oxygen to one of these haeme groups increases the affinity of the remaining sites for oxygen; this cooperation results in an S-shaped (sigmoidal) binding curve. The shape of this curve is influenced by pH and the presence of 2,3-Bisphosphoglycerate (2,3-BPG). Mutations in the genes for either the '-or the "-subunits of haemoglobin can cause serious disease.