Catalytic Site Atlas
LITERATURE entry for 1ca2
|E.C. name||carbonate dehydratase|
|Species||Homo sapiens (Human)|
E.C. Number (IntEnz)
|CSA Homologues of 1ca2||There are 321 Homologs
CSA Entries With UniProtID
CSA Entries With EC Number
|MACiE Entry ||M0216|
|Introduction||Carbonic acid anhydrase is able to catalyse the conversion of carbon dioxide to carbonic acid and vice versa. This is important in metabolism because it enables the creation of carbonic acid, a very important buffer in the blood which has a vital role in human physiology.|
|Mechansim||The reaction proceeds in two steps. First, an OH- bound to the Zinc ion attacks the carbon dioxide substrate forming bicarbonate and leaving a water at the Zinc ion. Polarisation of the C=O bond of carbon dioxide is achieved by Thr 199. Following this step, the OH- is regenerated by deprotonation of a water molecule by His 64, with Zinc acting to increase the polarity of the OH bond by withdrawing electrons from the oxygen atom.|
Catalytic Sites for 1ca2
| Annotated By Reference To The Literature - Site 2 (Perform Site Search)|
|Residue||Chain||Number||UniProtKB Number||Functional Part||Function||Target||Description|
|Thr||A||199||macie:sideChain||The interaction between the Thr199 and hydroxide serve to enhance the nucleophilicity of the hydroxide and help orient the substrate (CO2) in the active site.|
|His||A||64||64||macie:sideChain||Is able to deprotonate a water molecule allowing the formation of the catalytic nucleophile OH-.|
|Glu||A||106||macie:sideChain||Hydrogen bonds to the hydroxyl of Thr199, activiating it|
Refined structure of human carbonic anhydrase II at 2.0 A resolution.
Proteins 1988 4 274-282
Structural and kinetic characterization of active-site histidine as a proton shuttle in catalysis by human carbonic anhydrase II.
Biochemistry 2005 44 1097-1105
Role of histidine 64 in the catalytic mechanism of human carbonic anhydrase II studied with a site-specific mutant.
Biochemistry 1989 28 7913-7918
Crystal structure of carbonic anhydrase from Neisseria gonorrhoeae and its complex with the inhibitor acetazolamide.
J Mol Biol 1998 283 301-310
Carbonic anhydrase inhibitors.
Med Res Rev 2003 23 146-189
Structure and mechanism of carbonic anhydrase.
Pharmacol Ther 1997 74 1-20