IUBMB Enzyme Nomenclature

EC 4.2.1.104

Accepted name: cyanase

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 (1) can be considered as the reverse of 'carbamate = cyanate + H2O', where this is assisted by reaction with bicarbonate and carbon dioxide (see mechanism above) [2], and hence is classified in sub-subclass 4.2.1. Bicarbonate functions as a recycling substrate [2].

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, UM-BBD, 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]

[EC 4.2.1.104 created 1972 as EC 3.5.5.3, transferred 1990 to EC 4.3.99.1, transferred 2001 to EC 4.2.1.104, modified 2007]


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