Catalyzes the reversible hydration of carbon dioxide into bicarbonate and protons and thus is essential to maintaining intracellular and extracellular pH (     ). May stimulate the sodium/bicarbonate transporter activity of SLC4A4 that acts in pH homeostasis . It is essential for acid overload removal from the retina and retina epithelium, and acid release in the choriocapillaris in the choroid .
Subcellular locations: Cell membrane
Expressed in the endothelium of the choriocapillaris in eyes (at protein level). Not expressed in the retinal epithelium at detectable levels.