Cooperative Effect
The cooperative effect describes the ability of the four identical haemoglobin subunits to change their conformation.
The cause of this change is the acceptance or release of an O2 molecule by one of the subunits, which increases the ability of the other haemoglobin domains to accept or release oxygen.
A macroscopic consequence of this molecular effect is the ability of haemoglobin to bind oxygen depending on the partial pressure of oxygen and the pH value.
This means that more O2 is bound by haemoglobin in the lungs (high partial pressure of O2, high pH value) and that oxygen tends to be released in muscle tissue (low O2 partial pressure, low pH due to a higher CO2 partial pressure).
Movement at the haeme center |
Movement in one subunit |
Movement of the four subunits by binding and release of O2 |