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n. (context chemistry English) the enzyme, found in soil bacteria and some plants, that catalyzes the hydrolysis of urea into ammonia and carbon dioxide


n. an enzyme that catalyzes the hydrolysis of urea into carbon dioxide and ammonia; is present in intestinal bacteria


Ureases , functionally, belong to the superfamily of amidohydrolases and phosphotriesterases. It is an enzyme that catalyzes the hydrolysis of urea into carbon dioxide and ammonia. The reaction occurs as follows:

(NH)CO + HO → CO + 2 NH

More specifically, urease catalyzes the hydrolysis of urea to produce ammonia and carbamate; the carbamate produced is subsequently degraded by spontaneous hydrolysis to produce another ammonia and carbonic acid. Urease activity tends to increase the pH of its environment as it produces ammonia, a basic molecule. Ureases are found in numerous bacteria, fungi, algae, plants and some invertebrates, as well as in soils, as a soil enzyme. They are nickel-containing metalloenzymes of high molecular weight.

In 1926, James B. Sumner, an assistant professor at Cornell University, showed that urease is a protein by examining its crystallized form. Sumner's work was the first demonstration that a pure protein can function as an enzyme, and led eventually to the recognition that most enzymes are in fact proteins, and the award of the Nobel prize in chemistry to Sumner in 1946. The structure of urease was first solved by P. A. Karplus in 1995. Urease was the first ever enzyme crystallized.