Uréase | EPFL Graph Search

Ureases (), functionally, belong to the superfamily of amidohydrolases and phosphotriesterases. 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. These enzymes catalyze the hydrolysis of urea into carbon dioxide and ammonia: (NH2)2CO + H2O CO2 + 2NH3 The hydrolysis of urea occurs in two stages. In the first stage, ammonia and carbamic acid are produced. The carbamate spontaneously and rapidly hydrolyzes to ammonia and carbonic acid. Urease activity increases the pH of its environment as ammonia is produced, which is basic. Its activity was first identified in 1876 by Frédéric Alphonse Musculus as a soluble ferment. In 1926, James B. Sumner, showed that urease is a protein by examining its crystallized form. Sumner's work was the first demonstration that a protein can function as an enzyme and led eventually to the recognition that most enzymes are in fact proteins. Urease was the first enzyme crystallized. For this work, Sumner was awarded the Nobel prize in chemistry in 1946. The crystal structure of urease was first solved by P. A. Karplus in 1995. A 1984 study focusing on urease from jack bean found that the active site contains a pair of nickel centers. In vitro activation also has been achieved with manganese and cobalt in place of nickel. Lead salts are inhibiting. The molecular weight is either 480 kDa or 545 kDa for jack-bean urease (calculated mass from the amino acid sequence). 840 amino acids per molecule, of which 90 are cysteine residues. The optimum pH is 7.4 and optimum temperature is 60 °C. Substrates include urea and hydroxyurea. Bacterial ureases are composed of three distinct subunits, one large catalytic (α 60–76kDa) and two small (β 8–21 kDa, γ 6–14 kDa) commonly forming (αβγ)3 trimers stoichiometry with a 2-fold symmetric structure (note that the image above gives the structure of the asymmetric unit, one-third of the true biological assembly), they are cysteine-rich enzymes, resulting in the enzyme molar masses between 190 and 300kDa.

Neurometabolic profiles of bile duct ligated rats after the treatment with an urease inhibitor – 1H MRS dataset

Cristina Ramona Cudalbu, Dunja Simicic

1H MRS in the cerebellum was used to study the effect of 2-octynohydroxamic acid (2-octynoHA) treatment on the brain of bile duct ligated (BDL) rats (type C hepatic encephalopathy). The study included four groups of rats: negative control group (rats recei ...

Zenodo2023

Optical Urea Sensing in Sweat for Kidney Healthcare by Sensitive and Selective Non-enhanced Raman Spectroscopy

Christian Enz, Sandro Carrara, Assim Boukhayma, Ata Jedari Golparvar, Mattia Petrelli

Sweat biomarker analysis has attracted much interest in applications ranging from sports to wearable healthcare. Among all the sweat biomolecules, abnormal urea levels have been linked to several complications, particularly renal dysfunction. Here, we repo ...

SPIE-INT SOC OPTICAL ENGINEERING2023

Boosting hydrogen production via urea electrolysis on an amorphous nickel phosphide/graphene hybrid structure

Paul Joseph Dyson, Zhaofu Fei, Lu Chen, Yun Tong

Overall urea electrolysis has favorable thermodynamic properties and can complement traditional water splitting by simultaneously purifying urea-rich waste streams. However, the kinetics of the reaction is slow and more efficient catalysts are required. In ...

SPRINGER2021