CA12 Human

Carbonic Anhydrase XII (CA XII) is a member of the carbonic anhydrase family, which are zinc metalloenzymes that catalyze the reversible hydration of carbon dioxide. This enzyme plays a crucial role in various physiological processes, including respiration, acid-base balance, and the formation of bodily fluids such as saliva and gastric acid. CA XII is a type I membrane enzyme with an N-terminal extracellular catalytic domain, a membrane-spanning α-helix, and a small intracellular C-terminal domain. It is highly expressed in tissues such as the colon, kidney, and prostate, and is also found in activated lymphocytes .

The recombinant production of human CA XII involves several steps, starting with the cloning of the CA12 gene sequences. The catalytic domain encoding sequences are constructed and expressed in suitable host cells, such as bacterial or mammalian cell cultures. The recombinant protein is then purified using techniques like Ni²⁺-chelation chromatography or ligand-affinity chromatography. The purity of the recombinant CA XII is confirmed by SDS-PAGE and other analytical methods .

Carbonic Anhydrase XII catalyzes the reversible hydration of carbon dioxide to bicarbonate and protons:

$$\text{CO}_2 + \text{H}_2\text{O} \leftrightarrow \text{HCO}_3^- + \text{H}^+$$

This reaction is fundamental to many physiological processes, including respiration and renal tubular acidification. The enzyme uses a zinc hydroxide mechanism to achieve this reaction at physiological pH, making it one of the most efficient catalysts known in nature .