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Urease

 
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Urease
 
 
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Urease is an enzyme
Enzyme

Enzymes are biomolecules that catalysis chemical reactions. Almost all enzymes are proteins. In enzymatic reactions, the molecules at the beginning of the process are called Substrate , and the enzyme converts them into different molecules, the products....
 that catalyzes
Catalysis

Catalysis is the process in which the reaction rate of a chemical reaction is either increased or decreased by means of a chemical substance known as a catalyst....
 the hydrolysis
Hydrolysis

Hydrolysis is a chemical reaction during which one or more water are split into hydrogen and hydroxide ions which may go on to participate in further reactions....
 of urea
Urea

Urea is an organic compound with the chemical formula 2carbonoxygen.Urea is also known by the International Nonproprietary Name carbamide, as established by the World Health Organization....
 into carbon dioxide
Carbon dioxide

Carbon dioxide is a chemical compound composed of two oxygen atoms covalent bond to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state....
 and ammonia
Ammonia

Ammonia is a chemical compound with the chemical formula nitrogenhydrogen. It is normally encountered as a gas with a characteristic pungent odor....
. The reaction occurs as follows:

(NH2)2CO
Urea

Urea is an organic compound with the chemical formula 2carbonoxygen.Urea is also known by the International Nonproprietary Name carbamide, as established by the World Health Organization....
 + H2O ? CO2
Carbon dioxide

Carbon dioxide is a chemical compound composed of two oxygen atoms covalent bond to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state....
 + 2NH3
Ammonia

Ammonia is a chemical compound with the chemical formula nitrogenhydrogen. It is normally encountered as a gas with a characteristic pungent odor....


In 1926 James Sumner showed that urease is a protein
Protein

Proteins are organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid Residue ....
. Urease is found in bacteria, yeast
Yeast

Yeasts are eukaryote microorganisms classified in the Kingdom fungus, with about 1,500 species currently described; they dominate fungal diversity in the oceans....
 and several higher plant
Plant

Plants are Life organisms belonging to the Kingdom Plantae. They include familiar organisms such as trees, herbs, bushes, grasses, vines, ferns, mosses, and green algae....
s.


The multi-subunit enzyme usually has a 3:3 (alpha:beta) 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).






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Encyclopedia


Urease 1e9z
Urease is an enzyme
Enzyme

Enzymes are biomolecules that catalysis chemical reactions. Almost all enzymes are proteins. In enzymatic reactions, the molecules at the beginning of the process are called Substrate , and the enzyme converts them into different molecules, the products....
 that catalyzes
Catalysis

Catalysis is the process in which the reaction rate of a chemical reaction is either increased or decreased by means of a chemical substance known as a catalyst....
 the hydrolysis
Hydrolysis

Hydrolysis is a chemical reaction during which one or more water are split into hydrogen and hydroxide ions which may go on to participate in further reactions....
 of urea
Urea

Urea is an organic compound with the chemical formula 2carbonoxygen.Urea is also known by the International Nonproprietary Name carbamide, as established by the World Health Organization....
 into carbon dioxide
Carbon dioxide

Carbon dioxide is a chemical compound composed of two oxygen atoms covalent bond to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state....
 and ammonia
Ammonia

Ammonia is a chemical compound with the chemical formula nitrogenhydrogen. It is normally encountered as a gas with a characteristic pungent odor....
. The reaction occurs as follows:

(NH2)2CO
Urea

Urea is an organic compound with the chemical formula 2carbonoxygen.Urea is also known by the International Nonproprietary Name carbamide, as established by the World Health Organization....
 + H2O ? CO2
Carbon dioxide

Carbon dioxide is a chemical compound composed of two oxygen atoms covalent bond to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state....
 + 2NH3
Ammonia

Ammonia is a chemical compound with the chemical formula nitrogenhydrogen. It is normally encountered as a gas with a characteristic pungent odor....


In 1926 James Sumner showed that urease is a protein
Protein

Proteins are organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid Residue ....
. Urease is found in bacteria, yeast
Yeast

Yeasts are eukaryote microorganisms classified in the Kingdom fungus, with about 1,500 species currently described; they dominate fungal diversity in the oceans....
 and several higher plant
Plant

Plants are Life organisms belonging to the Kingdom Plantae. They include familiar organisms such as trees, herbs, bushes, grasses, vines, ferns, mosses, and green algae....
s.

Characteristics

  • Active site
    Active site

    The active site of an enzyme contains the catalysis and binding sites. The structure and chemical properties of the active site allow the recognition and binding of the substrate ....
     metal: nickel(II)
  • Molecular weight: 480 kDa
    Atomic mass unit

    The unified atomic mass unit , or dalton or, sometimes, universal mass unit, is a Units of measurement of mass used to express atomic weight and molecular masses....
     or 545 kDa
    Atomic mass unit

    The unified atomic mass unit , or dalton or, sometimes, universal mass unit, is a Units of measurement of mass used to express atomic weight and molecular masses....
     for Jack Bean Urease (calculated mass from the amino acid sequence).
  • Optimum pH
    PH

    pH is a measure of the Acid or Base of a solution. It is defined as the cologarithm of the Activity of dissolved hydrogen ions . Hydrogen ion activity coefficients cannot be measured experimentally, so they are based on theoretical calculations....
    : 7.4
  • Optimum Temperature: 60 degrees Celsius
  • Enzymatic specificity: urea and hydroxyurea
    Hydroxyurea

    Hydroxyurea or hydroxycarbamide is an antineoplastic medication used in hematological malignancy, specifically polycythemia vera and essential thrombocytosis....
  • Inhibitor
    Enzyme inhibitor

    Enzyme inhibitors are molecules that bind to enzymes and decrease their enzyme activity. Since blocking an enzyme's activity can kill a pathogen or correct a metabolism imbalance, many drugs are enzyme inhibitors....
    s: heavy metals
    Heavy metals

    A heavy metal is a member of an ill-defined subset of elements that exhibit metallic properties, which would mainly include the transition metals, some metalloids, lanthanides, and actinides....


The multi-subunit enzyme usually has a 3:3 (alpha:beta) 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). An exceptional urease is found in Helicobacter pylori
Helicobacter pylori

Helicobacter pylori is a Gram-negative, microaerophile bacterium that inhabits various areas of the stomach and duodenum. It causes a chronic low-level inflammation of the stomach lining and is strongly linked to the development of duodenal and gastric peptic ulcers and stomach cancer bacteria....
, which combines four of the regular six subunit enzymes in an overall tetrahedral assembly of 24 subunits . This supra-molecular assembly is thought to confer additional stability for the enzyme in this organism, which functions to produce ammonia in order to neutralise gastric acid
Gastric acid

Gastric acid is one of the main secretions of the stomach, together with several enzymes and intrinsic factor. Chemically it is an acid solution with a pH of 1 to 2 in the stomach lumen , consisting mainly of hydrochloric acid , and large quantities of potassium chloride and sodium chloride ....
. The presence of urease is used in the diagnosis of Helicobacter
Helicobacter

Helicobacter is a genus of Gram-negative bacterium possessing a characteristic helix shape. They were initially considered to be members of the Campylobacter genus, but since 1989 they have been grouped in their own genus....
 species.

As diagnostic test

Many gastrointestinal or urinary tract pathogens produce urease, enabling the detection of urease to be used as a diagnostic to detect presence of pathogens.

Urease-positive pathogens include:
  • Helicobacter pylori
    Helicobacter pylori

    Helicobacter pylori is a Gram-negative, microaerophile bacterium that inhabits various areas of the stomach and duodenum. It causes a chronic low-level inflammation of the stomach lining and is strongly linked to the development of duodenal and gastric peptic ulcers and stomach cancer bacteria....
  • Enteric bacteria including Proteus
    Proteus (bacterium)

    Proteus is a genus of Gram-negative Proteobacteria....
    , Klebsiella
    Klebsiella

    Klebsiella is a genus of motility, Gram-negative, Oxidase test rod shaped bacteria with a prominent polysaccharide-based Capsule . Frequent human pathogens, Klebsiella organisms can lead to a wide range of disease states, notably pneumonia, urinary tract infections, septicemia, Ankylosing spondylitis, and soft tissue infections....
     and Serratia(?)
  • Ureaplasma urealyticum
    Ureaplasma urealyticum

    Ureaplasma urealyticum is a bacterium belonging to the family Mycoplasmataceae. Its type strain is T960.U. urealyticum is part of the normal genital flora of both men and women....
    , a relative of the mycoplasma
    Mycoplasma

    Mycoplasma is a genus of bacterium which lack a cell wall. Without a cell wall, they are unaffected by many common antibiotics such as penicillin or other beta-lactam antibiotics that target cell wall synthesis....
  • Cryptococcus
    Cryptococcus

    Cryptococcus is a genus of fungus. It grows in culture as a yeast. The perfect form or teleomorph is called Filobasidiella, but the imperfect form or anamorph is called Cryptococcus....
    , an opportunistic fungus


Other uses