Characteristics
- Active site
- Molecular weight: 480 kDa or 545 kDa for Jack Bean Urease (calculated mass from the amino acid sequence).
- Optimum pH: 7.4
- Optimum Temperature: 60 degrees Celsius
- Enzymatic specificity: urea and hydroxyurea
- Inhibitors: heavy metals (Pb- & Pb2+)
The multi-subunit enzyme usually has a 3:3 (alpha:beta) stoichiometry with a 2-fold symmetric structure (note that the image above gives the structure of the asymmetric unit, one-third of the true biological assembly). An exceptional urease is found in Helicobacter pylori, which combines four of the regular six-subunit enzymes in an overall tetrahedral assembly of 24 subunits . This supra-molecular assembly is thought to confer additional stability for the enzyme in this organism, which functions to produce ammonia in order to neutralise gastric acid. The presence of urease is used in the diagnosis of Helicobacter species.
Read more about this topic: Urease