title: Catalytic properties and inhibition of Cd2+-carbonic anhydrases.
abstract: Cd2+ derivatives of human carbonic anhydrases I and II and bovine red cell carbonic anhydrase (carbonate hydro-lyase, EC 4.2.1.1) have been prepared. The metal ion in these derivatives is readily displaced by Zn2+. The Cd2+-carbonic anhydrases have appreciable 4-nitrophenyl acetate hydrolase activities. These activities increase with pH as if dependent on the basic form of a group with pKa near 10. The Cd2+-carbonic anhydrases also have significant CO2 hydration activities. The Cd2+ derivatives are strongly inhibited by monovalent anions. In particular, I- is a much more potent inhibitor of the Cd2+ enzymes than of the native enzymes. Acetazolamide (5-acetylamido-1,3,4-thiadiazole 2-sulfonamide) is also a strong inhibitor although its affinity for the Cd2+ enzyme is less than its affinity for the native enzyme.
mesh_terms: D000086:Acetazolamide / Q000494:pharmacology; D000818:Animals; D000838:Anions; D001051:Apoenzymes / Q000378:metabolism; D002104:Cadmium / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D002257:Carbonic Anhydrase Inhibitors / Q000494:pharmacology; D002256:Carbonic Anhydrases / Q000378:metabolism*; D002417:Cattle; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007454:Iodides / Q000494:pharmacology; D007527:Isoenzymes / Q000378:metabolism*; D009596:Nitrophenols / Q000378:metabolism; D015032:Zinc / Q000378:metabolism
chemical_list: D000838:Anions; D001051:Apoenzymes; D002257:Carbonic Anhydrase Inhibitors; D007454:Iodides; D007527:Isoenzymes; D009596:Nitrophenols; D002104:Cadmium; D002245:Carbon Dioxide; C008642:4-nitrophenyl acetate; D002256:Carbonic Anhydrases; D015032:Zinc; D000086:Acetazolamide