User:Mmedich01/Urease

Urease is a bio-molecule found in smaller microorganisms and few animals urease is used to catalyze the hydrolysis reaction of urea. Urea is created by the conversion of ammonia to a non-harmful product which is then expelled as urea. In mammals urease is not used and the conversion process takes place in the liver and urea is then expelled off in mammal’s urine, hence the similarity in name between urine and urea. In bacteria, fungi, and other organisms urea is converted and expelled by the hydrolysis reaction that is catalyzed by urease. This process of “fixing” ammonia in bacteria is what makes legumes such an interesting plant. Legumes, such as soybeans, contain nodules within their root system that harbor the habitat for the ammonia/nitrogen fixing bacteria.

Nickel binds to urease in the enzyme catalysis process. Specifically, two nickels bind to the urease and as one becomes attached to the central carbon atom becomes more electrophilic but when the second one binds, the affinity for water increases which then triggers hydrolysis. This does modulate ligand pKa’s where the His 320 has a pKa of around 6.5 and the deprotonated state has a pKa of roughly 9.