Carbonic anhydrase (CA) is a zinc-containing enzyme that catalyzes the reversible hydration of carbon dioxide: CO2 + H2O ⇋ HCO3- + H+. Eight genetically distinct carbonic anhydrase enzyme families (α-, β-, γ- δ-, ζ-, η-, θ- and ι- CAs) were described to date. Carbonic anhydrases are involved in numerous physiological and pathological processes. Many of them are important therapeutic targets with the potential to be inhibited to treat a range of disorders including oedema, glaucoma, obesity, cancer, epilepsy, and osteoporosis.
The carbonic anhydrase reaction is involved in many physiological and pathological processes, including respiration and transport of CO2 and bicarbonate between metabolizing tissues and lungs; pH and CO2 homeostasis; electrolyte secretion in various tissues and organs; biosynthetic reactions (such as gluconeogenesis, lipogenesis, and ureagenesis); bone resorption; calcification; and tumorigenicity. α-CAs are Zn2+ metalloproteins expressed in animals, vertebrates, prokaryotes, fungi, algae, protozoa, and plants. Sixteen mammalian α-CA isoforms are known to be involved in many diseases such as glaucoma, edema, epilepsy, obesity, hypoxic tumors, neuropathic pain, arthritis, neurodegeneration, etc.