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| Enzyme Name | | Swiss-prot | KEGG |
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| P40881 |
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| Protein name | Carbonic anhydrase | carbonate dehydratasecarbonic anhydraseanhydrasecarbonate anhydrasecarbonic acid anhydrasecarboxyanhydrasecarbonic anhydrase Acarbonate hydro-lyase |
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| Synonyms | EC 4.2.1.1 |
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| KEGG pathways | | MAP code | Pathways |
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| MAP00910 | Nitrogen metabolism |
| Swiss-prot:Accession Number | P40881 |
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| Entry name | CAH_METTE |
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| Activity | H(2)CO(3) = CO(2) + H(2)O. |
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| Subunit | Homotetramer. |
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| Subcellular location |
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| Cofactor | Zinc. |
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| References for Catalytic Mechanism | | References | Sections | No. of steps in catalysis |
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| [1] | p.2324-2325 |
| | [2] | p.13124-13127 |
| | [3] | Fig.5, p.9228-9229 | 2 | | [4] | p.9237-9239 |
| | [5] | p.338 |
| | [7] | p.48617 |
| | [8] | p.675-676 |
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| references | | [1] |
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| Comments | X-RAY CRYSTALLOGRAPHY (2.8 ANGSTROMS). |
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| Medline ID | 96221292 |
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| PubMed ID | 8665839 |
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| Journal | EMBO J |
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| Year | 1996 |
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| Volume | 15 |
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| Pages | 2323-30 |
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| Authors | Kisker C, Schindelin H, Alber BE, Ferry JG, Rees DC |
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| Title | A left-hand beta-helix revealed by the crystal structure of a carbonic anhydrase from the archaeon Methanosarcina thermophila. |
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| Related PDB | 1thj |
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| Related Swiss-prot | P40881 |
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| [2] |
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| PubMed ID | 10529183 |
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| Journal | Biochemistry |
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| Year | 1999 |
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| Volume | 38 |
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| Pages | 13119-28 |
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| Authors | Alber BE, Colangelo CM, Dong J, Stalhandske CM, Baird TT, Tu C, Fierke CA, Silverman DN, Scott RA, Ferry JG |
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| Title | Kinetic and spectroscopic characterization of the gamma-carbonic anhydrase from the methanoarchaeon Methanosarcina thermophila. |
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| [3] |
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| Comments | X-RAY CRYSTALLOGRAPHY (1.46 ANGSTROMS). |
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| Medline ID | 20384208 |
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| PubMed ID | 10924115 |
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| Journal | Biochemistry |
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| Year | 2000 |
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| Volume | 39 |
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| Pages | 9222-31 |
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| Authors | Iverson TM, Alber BE, Kisker C, Ferry JG, Rees DC |
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| Title | A closer look at the active site of gamma-class carbonic anhydrases: high-resolution crystallographic studies of the carbonic anhydrase from Methanosarcina thermophila. |
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| Related PDB | 1qre,1qrf,1qrg,1qrl,1qrm,1qq0 |
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| Related Swiss-prot | P40881 |
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| [4] |
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| PubMed ID | 10924116 |
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| Journal | Biochemistry |
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| Year | 2000 |
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| Volume | 39 |
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| Pages | 9232-40 |
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| Authors | Tripp BC, Ferry JG |
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| Title | A structure-function study of a proton transport pathway in the gamma-class carbonic anhydrase from Methanosarcina thermophila. |
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| [5] |
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| PubMed ID | 10978542 |
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| Journal | FEMS Microbiol Rev |
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| Year | 2000 |
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| Volume | 24 |
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| Pages | 335-66 |
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| Authors | Smith KS, Ferry JG |
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| Title | Prokaryotic carbonic anhydrases. |
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| [6] |
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| PubMed ID | 11414818 |
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| Journal | J Am Chem Soc |
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| Year | 2001 |
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| Volume | 123 |
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| Pages | 5861-6 |
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| Authors | Tu C, Tripp BC, Ferry JG, Silverman DN |
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| Title | Bicarbonate as a proton donor in catalysis by Zn(II)- and Co(II)-containing carbonic anhydrases. |
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| [7] |
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| PubMed ID | 11696553 |
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| Journal | J Biol Chem |
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| Year | 2001 |
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| Volume | 276 |
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| Pages | 48615-8 |
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| Authors | Tripp BC, Smith K, Ferry JG |
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| Title | Carbonic anhydrase: new insights for an ancient enzyme. |
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| [8] |
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| PubMed ID | 11781108 |
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| Journal | Biochemistry |
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| Year | 2002 |
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| Volume | 41 |
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| Pages | 669-78 |
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| Authors | Tripp BC, Tu C, Ferry JG |
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| Title | Role of arginine 59 in the gamma-class carbonic anhydrases. |
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| [9] |
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| PubMed ID | 12484784 |
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| Journal | Biochemistry |
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| Year | 2002 |
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| Volume | 41 |
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| Pages | 15429-35 |
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| Authors | Tu C, Rowlett RS, Tripp BC, Ferry JG, Silverman DN |
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| Title | Chemical rescue of proton transfer in catalysis by carbonic anhydrases in the beta- and gamma-class. |
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| comments | This enzyme is belongs to the gamma -carbonic anhydorase enzyme family.
The catalytic zinc ion is ligated by three conserved histidine residues in a trigonal bipyramidal geometry with two more water ligands. (When cobalt ion is bound to this enzyme, the geometry is octahedral.) (see [3]). One of the ligating histidine residues, His117, is from a next chain.
According to the literature [3], [4], [7] & [8], the catalytic reaction proceeds as follows:
(1) A water molecule is bound to the cofactor zinc.
(2) A proton of the substrate water is abstracted by a proton shuttle residue, to generate the hydroxide. The proton of the zinc-bound water is transferred through Glu62 to Glu84. Thus, Glu62 acts as a general base to deprotonate the water, whilst Glu84 acts as a proton shuttle residue, which transfer the proton to the solvent.
(3) The hydroxide bound to the zinc makes a nucleophilic attack on the carbon atom of another substrate, carbon dioxide (CO2), which is probably stabilized by Arg59, Gln75' or Asn202' from the adjacent chain. (This attack seems to be SN1-like, according to the literature [3].) The nucleophile, the hydroxide, is also stabilized by Asp62. This reaction leads to the formation of the product, bicarbonate anion.
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| created | updated |
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| 2004-06-28 | 2009-02-26 |
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