2 H(+) + H2O + urea = CO2 + 2 NH4(+) Binds 2 nickel ions per subunit. Nitrogen metabolism; urea degradation; CO(2) and NH(3) from urea (urease route): step 1/1. Heterotrimer of UreA (gamma), UreB (beta) and UreC (alpha) subunits. Three heterotrimers associate to form the active enzyme. Carboxylation allows a single lysine to coordinate two nickel ions. Belongs to the metallo-dependent hydrolases superfamily. Urease alpha subunit family. The last gene of this probable operon, ureD, gives rise to a truncated protein. Absence of ureD prevents expression of active urease. Correction of the mutation does not effect virulence in mice in any detectable fashion, suggesting urease is not important in the virulence of Y.pestis (PubMed:11119503).