The CAIX works as adimeric molecule composed of two monomeric proteins liked with a disulfide bondbetween cysteine residues of the two CAIX monomers, while the structure ofCAXII is stabilized by 19 hydrogen-bonded interactions in the dimer interface. Carbonicanhydrases IX and CAXII (CAIX/CAXII) are transmembrane zinc metalloproteinsthat catalyze a very basic but crucial physiological reaction: the conversion ofcarbon dioxide into bicarbonate with a release of the proton.CAIX functionswith bicarbonate transporters (including electroneutral bicarbonate transporterNBCn1 (SLC4A7)) to bring in HCO3- produced in a CAIX-mediated hydrationreaction of CO2, and amino acid transporters (including the large neutral aminoacid transporter 1 (LAT1) and CD98 heavy chain (CD98hc)) to transport inessential amino acids and glutamine (via interaction with glutamine transporterSLC1A5 and sodium-coupled neutral amino acid transporter 2 (SNAT2) facilitatingthe uptake of aminoacid by SLC1A5), which cancer cells employ as an alternativemetabolic energy source and biosynthetic precursor. CAIX also creates uniqueinteractions with collagen- and laminin-binding integrins at the leading edgeof migrating cells.