Reaction: urea + 2 H2O = hydrogen carbonate + 2 NH3 (overall reaction)
(1a) urea + H2O = carbamate + NH3
(1b) carbamate + H2O = hydrogen carbonate + NH3 (spontaneous)
Systematic name: urea amidohydrolase
Comments: A nickel protein. Urease catalyses the hydrolysis of urea to yield ammonia and carbamate, which spontaneously hydrolyses to form carbonic acid and a second molecule of ammonia. In aqueous solutions the products convert to ammonium and hydrogen carbonate. The enzyme is widespread and is found in many bacteria, some archaea, and many eukaryotes, including plants, some invertebrates, and numerous eukaryotic microorganisms. Urease is one of the earlier enzymes to be studied, first obtained In 1874 [1,2], and named urease in 1890 [3]. The crystallization of urease in 1926 was a significant landmark in biochemistry, showing for the first time ever that enzymes are proteins and can be crystallized [4]. In 1975 it was found that the enzyme contains nickel ions in its active site [5,6].
Links to other databases: BRENDA, EAWAG-BBD, EXPASY, GTD, KEGG, MetaCyc, PDB, CAS registry number: 9002-13-5
References:
1. Musculus, F. Sur un Papier Reactif de l’Uree. Comptes Rendus 78 (1874) 132-134.
2. Musculus, F. Sur le Ferment de l’Uree. Comptes Rendus 82 (1876) 333-336.
3. Miquel, P. Sur un Ferment Soluble de l’Uree. Comptes Rendus 111 (1890) 397-399.
4. Sumner, J.B. The isolation and crystallization of the enzyme urease. Journal of Biological Chemistry 69(2) (1926) 435-441.
5. Dixon, N.E., Gazzola, T.C., Blakeley, R.L. and Zermer, B. Jack bean urease (EC 3.5.1.5). A metalloenzyme. A simple biological role for nickel? J. Am. Chem. Soc. 97 (1975) 4131-4133. [PMID: 1159216]
6. Dixon, N.E., Gazzola, C., Blakeley, R.L. and Zerner, B. Metal ions in enzymes using ammonia or amides. Science 191 (1976) 1144-1150. [PMID: 769157]
7. Sumner, J.B. Urease. In: Sumner, J.B. and Myrbäck, K. (Ed.), The Enzymes, vol. 1, Academic Press, New York, 1951, pp. 873-892.
8. Varner, J.E. Urease. In: Boyer, P.D., Lardy, H. and Myrbäck, K. (Ed.), The Enzymes, 2nd edn, vol. 4, Academic Press, New York, 1960, pp. 247-256.