How does carbonic acid anhydrase affect the equilibrium of the bicarbonate buffe

Carbonic anhydrase catalyzes the conversion of carbonic acid to dissolved carbon dioxide. In the lungs, excess dissolved carbon dioxide is exhaled as carbon dioxide gas.

The carbonic acid is converted through the action of the enzyme carbonic anhydrase into aqueous carbon dioxide.

This is the general equilibrium equation that describes the carbonic acid bicarbonate system:

CO2 (g) + H20 (l) <=> H2CO3 (aq) <=> H+ (aq) + HCO3- (aq)

The main job of the carbonic acid/bicarbonate system is to regulate body pH. The lungs expel CO2, which raises pH, because hydrogen ions have to be consumed with bicarbonate ions in order to produce CO2 (then there are less hydrogen ions floating around). To prevent too many hydrogens from being lost, the kidneys remove excess bicarbonate ions. As a result, the equilibrium is shifted to the right (so that more bicarbonate ions are produced to replace the lost ones), and as a result, more hydrogen ions are produced, which lowers the pH.

When your body uses energy to do work (such as exercising), lots of CO2 is produced. This CO2 is partially dissolved in plasma and red blood cells, but most of it ends up combining with water to form carbonic acid (H2CO3), which further dissociates into H+ ions and HCO3- ions. The enzyme that combines water and CO2 to make carbonic acid is called carbonic anhydrase. This occurs mainly in the capillaries of the circulation system. The bicarbonate (HCO3-) ions then are transported through the circulation system until they reach the lungs, when they combine with hydrogen ions to form CO2 and water. This CO2 is then expelled out by the lungs.