Urease

powder

Urease from Canavalia ensiformis may be used for urea determination of various samples, such as legumes. It may be useful for the detection of pathogens as well as heavy-metal ions.

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

Urease, an enzyme, converts urea into ammonium carbonate [(NH₄)₂CO₃] that releases ammonia. Thus, the enzyme activates the hydrolysis of urea. When the release occurs on or near the soil surface, ammonia is lost to the air; if it occurs near the seeds, they fail to germinate, or it proves to be toxic to the roots of young saplings. Crops can get affected by a high concentration of ammonia. Soybean, jack beans and a number of fungi are sources of urease. Its isoelectric point is pH 5.5.
Urease enzyme catalyzes the hydrolysis of urea which occurs readily in the soils. Large numbers of bacteria, fungi and actinomycetes in soils possess urease. A small group of bacteria, known as urea bacteria, have an exceptional ability to decompose urea. Activity increases in proportion with the size of the soil microbial population and the organic matter content. The presence of relatively fresh plant residues often results in abundant supplies of urease. The greatest activity of urease is reported to occur in the rhizosphere, where microbial activity is high and where it can be excreted from the plant roots.
Although warm temperature (up to 37°C) favors urease activity, the hydrolysis of urea occurs at significant rates at temperatures down to 2°C. The effects of soil moisture levels on urease activity are generally small in comparison to the influence of the pH and temperature. Free ammonia inhibits the enzymatic action of urease.