Definitions

# Urease

[yoor-ee-eys, -eyz]
Urease is an enzyme that catalyzes the hydrolysis of urea into carbon dioxide and ammonia. The reaction occurs as follows:

(NH2)2CO + H2O → CO2 + 2NH3
Urea + Water --urease--> Ammonium Carbonate
In 1926 James Sumner showed that urease is a protein. Urease is found in bacteria, yeast and several higher plants.

## Characteristics

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 ($alpha_\left\{12\right\}beta_\left\{12\right\}$). 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

Many gastrointestinal or urinary tract pathogens produce urease, enabling the detection of urease to be used as a diagnostic to detect presence of pathogens.

Urease-positive pathogens include:

## Other uses

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