Urease
You don't need to be Editor-In-Chief to add or edit content to WikiDoc. You can begin to add to or edit text on this WikiDoc page by clicking on the edit button at the top of this page. Next enter or edit the information that you would like to appear here. Once you are done editing, scroll down and click the Save page button at the bottom of the page.
Urease (EC 3.5.1.5) is an enzyme that catalyzes the hydrolysis of urea into carbon dioxide and ammonia. The reaction occurs as follows:
In 1926 James Sumner showed that urease is a protein. Urease is found in bacteria, yeast and several higher plants.
Characteristics:
- Active site metal: nickel(II)
- 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
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 (α12β12). 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.
As diagnostic test
Organisms that produce urease tend to be gastrointestinal or urinary tract pathogens, since urease enables them to neutralize the acid present in these acidic environments.
Urease-positive pathogens include:
- Helicobacter pylori
- Enteric bacteria including Proteus, Klebsiella and Serratia
- Ureaplasma urealyticum, a relative of the mycoplasma
- Cryptococcus, an opportunistic fungus
| This hydrolase article is a stub. You can help WikiDoc by expanding it. |
Carbon-nitrogen non-peptide hydrolases (EC 3.5) | |
|---|---|
| 3.5.1 - Amidohydrolases | Asparaginase - Glutaminase - Urease - Biotinidase - Aspartoacylase - Ceramidase -Aspartylglucosaminidase - Fatty acid amide hydrolase - Histone deacetylase (Sirtuin) |
| 3.5.2 | Barbiturase - Beta-lactamase |
| 3.5.3 | Arginase |
| 3.5.4 - Aminohydrolases | Guanine deaminase - Adenosine deaminase - AMP deaminase - Inosine monophosphate synthase - DCMP deaminase - GTP cyclohydrolase I |
| Other | Nitrilase - Thiaminase II |
cy:Wreas da:Urease de:Ureaseit:Ureasi he:אוראז ja:ウレアーゼuk:Уреаза
Acknowledgement and Attribution Regarding Sources of Content
Some of the initial content on this page may be incorporated in part from copyleft sources in the public domain including wikis such as Wikipedia and AskDrWiki. Drug information for patients came from the The National Library of Medicine. Infectious disease information may have come from the Centers for Disease Control (CDC). Differential Diagnoses are drawn from clinicians as well as an amalgamation of 3 sources: 1.The Disease Database; 2. Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:3; 3. Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:7 .
