Carbonicanhydrase

Carbonic anhydrase is a group of zinc-containing metalloenzymes that catalyze the reversible hydration of carbon dioxide (CO₂) to bicarbonate (HCO₃⁻) and a proton (H⁺). This reaction is critical for maintaining acid-base balance, transporting CO₂ in biological systems, and facilitating various physiological processes.

The enzyme was first discovered in 1932 by Danish biochemist Christian Bohr’s son, Dane Kogl, and later named by biochemist Warren L. Dawson in 1940. Carbonic anhydrase exists in multiple isoforms, with the most well-studied being carbonic anhydrase II (CA II), which is highly active and found in red blood cells, gastric parietal cells, and renal tubular cells. Other isoforms, such as CA I, CA IV, and CA IX, are localized to different tissues and play specialized roles.

The active site of carbonic anhydrase contains a zinc ion coordinated by three histidine residues, which facilitates the catalytic conversion of CO₂ to bicarbonate. This reaction is essential for respiration, as it enables efficient CO₂ transport from tissues to the lungs and bicarbonate reabsorption in the kidneys. Carbonic anhydrase inhibitors, such as acetazolamide, are used therapeutically to manage conditions like glaucoma, epilepsy, and altitude sickness by altering pH and fluid balance.

The enzyme also plays roles in bone resorption, calcification, and certain pathological processes, including cancer progression and ocular hypertension. Genetic deficiencies in carbonic anhydrase can lead to metabolic disorders, emphasizing its importance in human physiology. Research continues to explore its potential as a drug target for various diseases.