Carbonic anhydrase 1 (CA1) (CA1)

Carbonic anhydrase 1 (CA1) is a cytosolic zinc-containing metalloenzyme that plays a vital role in the systemic transport of carbon dioxide and the regulation of acid-base homeostasis [1][2]. It is predominantly expressed in erythrocytes and the gastrointestinal tract, where it catalyzes the reversible hydration of CO2 to bicarbonate and a proton [3]. Although CA1 possesses lower catalytic activity compared to the CA2 isoform, its high concentration in red blood cells makes it essential for respiratory gas exchange [1][4]. Therapeutically, CA1 is targeted by sulfonamide-based inhibitors such as acetazolamide, which are used to treat glaucoma, altitude sickness, and edema by reducing fluid production and altering pH [3][5]. Beyond its classical roles, CA1 has been implicated as an autoantigen in Sjogren's syndrome and Ankylosing spondylitis, and its expression levels are studied as biomarkers for vascular health and certain cancers [6][7]. Its lack of selective inhibitors often results in systemic off-target effects, presenting a persistent challenge for isoform-specific drug design [5][8].

Other names

Carbonate dehydratase ICA-ICABCarbonic anhydrase BCarbonic dehydratase

Competitive inhibition of the enzyme's active site by binding to the catalytic zinc ion, which prevents the hydration of carbon dioxide and the subsequent production of bicarbonate and protons [3][5].