Urease from Canavalia ensiformis (Jack bean)

Subunit molecular weight: ~90,770
Composed of six subunits with total molecular weight: ~544,620

Urease is a cytosolic enzyme that catalyzes the hydrolysis of urea to ammonia and carbon dioxide, with initial conversion to carbamate, and the carbamate breaks down further, on hydrolysis, into ammonia and to carbonic acid / carbonate. Urease is a metalloenzyme that contains nickel as a co-factor. Urease occurs naturally in plants, fungi, and certain bacteria. James B. Sumner first isolated urease from jack bean in 1926.

Urease from Canavalia ensiformis functions as an insecticide by the release of a toxic small peptide cleaved by proteases found in the gut of insects.

One micromolar unit will liberate 1.0 μmole of NH₃ from urea per min at pH 7.0 at 25 °C. It is equivalent to 1.0 I.U. or 0.054 Sumner unit (1.0 mg ammonia nitrogen in 5 minutes at pH 7.0 at 20 °C)