Reaction: cyanate + HCO3– + 2 H+ = NH3 + 2 CO2 (overall reaction)
(1a) cyanate + HCO3– + H+ = carbamate + CO2
(1b) carbamate + H+ = NH3 + CO2 (spontaneous)
For diagram click here.
Glossary: cyanate = NCO-
carbamate = H2N-CO-O-
Other name(s): cyanate lyase; cyanate hydrolase; cyanase; cyanate aminohydrolase; cyanate C-N-lyase; cyanate hydratase
Systematic name: carbamate hydro-lyase
Comments: This enzyme, which is found in bacteria and plants, is used to decompose cyanate, which can be used as the sole source of nitrogen [6,7]. Reaction (1a) can be considered an equivalent of 'cyanate + H2O = carbamate', where the water molecule is provided by the dehydration of bicarbonate to carbon dioxide [2], and hence the enzyme is classified as a hydrolase.
Links to other databases: BRENDA, EAWAG-BBD, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 37289-24-0
References:
1. Anderson, P.M. Purification and properties of the inducible enzyme cyanase. Biochemistry 19 (1980) 2882-2888. [PMID: 6994799]
2. Johnson, W.V. and Anderson, P.M. Bicarbonate is a recycling substrate for cyanase. J. Biol. Chem. 262 (1987) 9021-9025. [PMID: 3110153]
3. Taussig, A. The synthesis of the induced enzyme, "cyanase", in E. coli. Biochim. Biophys. Acta 44 (1960) 510-519. [PMID: 13775509]
4. Taussig, A. Some properties of the induced enzyme cyanase. Can. J. Biochem. 43 (1965) 1063-1069. [PMID: 5322950]
5. Anderson, P.M., Korte, J.J. and Holcomb, T.A. Reaction of the N-terminal methionine residues in cyanase with diethylpyrocarbonate. Biochemistry 33 (1994) 14121-14125. [PMID: 7947823]
6. Kozliak, E.I., Fuchs, J.A., Guilloton, M.B. and Anderson, P.M. Role of bicarbonate/CO2 in the inhibition of Escherichia coli growth by cyanate. J. Bacteriol. 177 (1995) 3213-3219. [PMID: 7768821]
7. Walsh, M.A., Otwinowski, Z., Perrakis, A., Anderson, P.M. and Joachimiak, A. Structure of cyanase reveals that a novel dimeric and decameric arrangement of subunits is required for formation of the enzyme active site. Structure 8 (2000) 505-514. [PMID: 10801492]