Urease, Recombinant

Blue Ice

83, 1

Supplied as a powder lyophilized from a solution containing potassium phosphate and disodium EDTA. Reconstitute with sterile dH2O.

Urease (EC3.5.1.5) is an enzyme that catalyzes the hydrolysis of urea into carbon dioxide and ammonia. The reaction occurs as follows: (NH2)2CO+H2O --> CO2+2NH3. In 1926 James Sumner showed that urease is a protein. Urease is found in bacteria, yeast and several higher plants. The multi-subunit enzyme usually has a 3:3 (alpha:beta) stoichiometry with a 2-fold symmetric structure. 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.

Product Description:
This product is a genetically designed mutant Urease with a shifted substrate affinity (high Km) to urea, making it suitable for kinetic urea assay under a wider measurable range.  It was designed from a wild type coding gene from Enterobacter aerogenes. Three different sub-units in an alpha2, beta4 and gamma4 (60.3kD, 11.7kD and 11.1kD, respectively) quaternary structure make up the fully active form.

Specific Activity:
~140IU/mg (lot-specific; value may vary form lot to lot)

Unit Definition:
One Unit oxidizes one micromole of NADH/minute at 25°C, at pH 7.6.

Active Site Metal:
Nickel(II)

Optimum pH:
7.4

Optimum Temperature:
60°C

Enzymatic Specificity:
Urea and hydroxyurea

Inhibitors:
Heavy metals

Storage and Stability:
Lyophilized powder may be stored at -20°C. Stable for 12 months after receipt at -20°C. Reconstitute with sterile buffer or ddH2O. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Reconstituted product is stable for 6 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.