Carbonic Anhydrases and their Physiological Roles

Carbonic anhydrase is an omnipresent zinc-containing metalloenzyme which is essential for a lot of physiological activities because of its property to convert CO₂ to HCO₃^- reversibly. It is one of the fastest enzymes known for hydrating 106 molecules of CO₂ per second. The rate of reaction of this enzyme is typically limited by the rate of diffusion of its substrates. There are six types of carbonic anhydrases- alpha, beta, gamma, delta, epsilon and zeta, named by greek letters. Carbonic anhydrase is often arranged in clusters along membranes or localised in extracellular spaces, which may contribute to the ability of carbonic anhydrase to facilitate the intracellular diffusion of carbon dioxide and protons (H⁺). By increasing the movement of protons, carbonic anhydrase can dissipate intracellular pH gradients, thereby helping the cell to maintain a uniform cellular pH. Overall, the uses of Carbonic anhydrase are multifold which will be later discussed in this paper.