Urease - wikipedia Urease Urease Helicobacter pylori Urease drawn from PDB : 1E9Z ​. Identifiers EC number 3.5. 1.5 CAS number 9002 - 13 - 5 Databases IntEnz IntEnz view BRENDA BRENDA entry ExPASy NiceZyme view KEGG KEGG entry MetaCyc metabolic pathway PRIAM profile PDB structures RCSB PDB PDBe PDBsum Search PMC articles PubMed articles NCBI proteins Ureases ( EC 3.5. 1.5 ), 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 + H O → 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. Its activity was first identified in 1876 by Frédéric Alphonse Musculus as a soluble ferment. 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. Contents 1 Characteristics 2 Active site 3 Activity 4 Proposed mechanisms 4.1 Blakeley / Zerner 4.2 Hausinger / Karplus 4.3 Ciurli / Mangani 5 Action in pathogenesis 6 Environmental Significance 7 As diagnostic test 8 Extraction 9 See also 10 References 11 External links Characteristics Active site requiring nickel in jack - bean and several bacteria. However, in vitro activation also has been achieved with manganese and cobalt Molecular weight : 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 cysteines. Optimum pH : 7.4 Optimum Temperature : 60 degrees Celsius Enzymatic specificity : urea and hydroxyurea Inhibitors : heavy metals ( Pb & Pb ) Bacterial ureases are composed of three distinct subunits, one large ( 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. An exceptional enzyme is the urease of Helicobacter species, which is composed of two subunits, α ( 26 -- 31 kDa ) - β ( 61 -- 66 kDa ), and has been shown to form a supramolecular dodecameric complex. of repeating α - β subunits, each coupled pair of subunits has an active site, for a total of 12 active sites. ( α 12 β 12 ( displaystyle alpha _ ( 12 ) \beta _ ( 12 ) ) ). It plays an essential function for survival, neutralizing gastric acid by allowing urea to enter into periplasm via a proton - gated urea channel. The presence of urease is used in the diagnosis of Helicobacter species. All bacterial ureases are solely cytoplasmic, except for Helicobacter pylori urease, which along with its cytoplasmic activity, has external activity with host cells. In contrast, all plant ureases are cytoplasmic. Fungal and plant ureases are made up of identical subunits ( ~ 90 kDa each ), most commonly assembled as trimers and hexamers. For example, jack - bean urease has two structural and one catalytic subunit. The α subunit contains the active site, it is composed of 840 amino acids per molecule ( 90 cysteines ), its molecular mass without Ni ( II ) ions amounting to 90.77 kDa. The mass of the hexamer with the 12 nickel ions is 545.34 kDa. It is structurally related to the ( αβγ ) 3 trimer of bacterial ureases. Other examples of homohexameric structures of plant ureases are those of soybean, pigeon pea and cotton seeds enzymes. It is important to note, that although composed of different types of subunits, ureases from different sources extending from bacteria to plants and fungi exhibit high homology of amino acid sequences. Active site The active site of all ureases known are located in the α ( alpha ) subunits. It is a bis - μ - hydroxo dimeric nickel center, with an interatomic distance of ~ 3.5 Å, magnetic susceptibility experiments have indicated that, in jack bean urease, high spin octahedrally coordinated Ni ( II ) ions are weakly antiferromagnetically coupled. X-ray absorption spectroscopy ( XAS ) studies of Canavalia ensiformis ( jack bean ), Klebsiella aerogenes and Sporosarcina pasteurii ( formerly known as Bacillus pasteurii ) confirm 5 -- 6 coordinate nickel ions with exclusively O / N ligands ( two imidazoles per nickel ). The water molecules are located towards the opening of the active site and form a tetrahedral cluster that fills the cavity site through hydrogen bonds, and it 's here where urea binds to the active site for the reaction, displacing the water molecules. The amino acid residues participate in the substrate binding, mainly through hydrogen bonding, stabilize the catalytic transition state and accelerate the reaction. Additionally, the amino acid residues involved in the architecture of the active site compose part of the mobile flap of the site, which is said to act as a gate for the substrate. Cysteine residues are common in the flap region of the enzymes, which have been determined not to be essential in catalysis, although involved in positioning other key residues in the active site appropriately. In the structure of Sporosarcina pasteurii urease the flap was found in the open conformation, while its closed conformation is apparently needed for the reaction. When compared, the α subunits of Helicobacter pylori urease and other bacterial ureases align with the jack bean ureases, suggesting that all ureases are evolutionary variants of one ancestral enzyme. It is important to note that the coordination of urea to the active site of urease has never been observed in a resting state of the enzyme. Activity The k / K of urease in the processing of urea is 10 times greater than the rate of the uncatalyzed elimination reaction of urea. There are many reasons for this observation in nature. The proximity of urea to active groups in the active site along with the correct orientation of urea allow hydrolysis to occur rapidly. Urea alone is very stable due to the resonance forms it can adopt. The stability of urea is understood to be due to its resonance energy, which has been estimated at 30 -- 40 kcal / mol. This is because the zwitterionic resonance forms all donate electrons to the carbonyl carbon making it less of an electrophile making it less reactive to nucleophilic attack. Proposed mechanisms Blakeley / Zerner One mechanism for the catalysis of this reaction by urease was proposed by Blakely and Zerner. It begins with a nucleophilic attack by the carbonyl oxygen of the urea molecule onto the 5 - coordinate Ni ( Ni - 1 ). A weakly coordinated water ligand is displaced in its place. A lone pair of electrons from one of the nitrogen atoms on the Urea molecule creates a double bond with the central carbon, and the resulting NH of the coordinated substrate interacts with a nearby negatively charged group. Blakeley and Zerner proposed this nearby group to be a Carboxylate ion A hydroxide ligand on the six coordinate Ni is deprotonated by a base. The carbonyl carbon is subsequently attacked by the electronegative oxygen. A pair of electrons from the nitrogen - carbon double bond returns to the nitrogen and neutralizes the charge on it, while the now 4 - coordinate carbon assumes an intermediate tetrahedral orientation. The breakdown of this intermediate is then helped by a sulfhydryl group of a cysteine located near the active site. A hydrogen bonds to one of the nitrogen atoms, breaking its bond with carbon, and releasing an NH3 molecule. Simultaneously, the bond between the oxygen and the 6 - coordinate nickel is broken. This leaves a carbamate ion coordinated to the 5 - coordinate Ni, which is then displaced by a water molecule, regenerating the enzyme. The carbamate produced then spontaneously degrades to produce another ammonia and carbonic acid. Hausinger / Karplus The mechanism proposed by Hausinger and Karplus attempts to revise some of the issues apparent in the Blakely and Zerner pathway, and focuses on the positions of the side chains making up the urea - binding pocket. From the crystal structures from K. aerogenes urease, it was argued that the general base used in the Blakely mechanism, His, was too far away from the Ni2 - bound water to deprotonate in order to form the attacking hydroxide moiety. In addition, the general acidic ligand required to protonate the urea nitrogen was not identified. Hausinger and Karplus suggests a reverse protonation scheme, where a protonated form of the His ligand plays the role of the general acid and the Ni2 - bound water is already in the deprotonated state. The mechanism follows the same path, with the general base omitted ( as there is no more need for it ) and His donating its proton to form the ammonia molecule, which is then released from the enzyme. While the majority of the His ligands and bound water will not be in their active forms ( protonated and deprotonated, respectively, ) it was calculated that approximately 0.3 % of total urease enzyme would be active at any one time. While logically, this would imply that the enzyme is not very efficient, contrary to established knowledge, usage of the reverse protonation scheme provides an advantage in increased reactivity for the active form, balancing out the disadvantage. Placing the His ligand as an essential component in the mechanism also takes into account the mobile flap region of the enzyme. As this histidine ligand is part of the mobile flap, binding of the urea substrate for catalysis closes this flap over the active site and with the addition of the hydrogen bonding pattern to urea from other ligands in the pocket, speaks to the selectivity of the urease enzyme for urea. Ciurli / Mangani The mechanism proposed by Ciurli and Mangani is one of the more recent and currently accepted views of the mechanism of urease and is based primarily on the different roles of the two nickel ions in the active site. One of which binds and activates urea, the other nickel ion binds and activates the nucleophilic water molecule. With regards to this proposal, urea enters the active site cavity when the mobile ' flap ' ( which allows for the entrance of urea into the active site ) is open. Stability of the binding of urea to the active site is achieved via a hydrogen - bonding network, orienting the substrate into the catalytic cavity. Urea binds to the five - coordinated nickel ( Ni1 ) with the carbonyl oxygen atom. It approaches the six - coordinated nickel ( Ni2 ) with one of its amino groups and subsequently bridges the two nickel centers. The binding of the urea carbonyl oxygen atom to Ni1 is stabilized through the protonation state of His Nԑ. Additionally, the conformational change from the open to closed state of the mobile flap generates a rearrangement of Ala carbonyl group in such a way that its oxygen atom points to Ni2. The Ala and Ala are now oriented in a way that their carbonyl groups act as hydrogen - bond acceptors towards NH group of urea, thus aiding its binding to Ni2. Urea is a very poor chelating ligand due to low Lewis base character of its NH groups. However the carbonyl oxygens of Ala and Ala enhance the basicity of the NH groups and allow for binding to Ni2. Therefore, in this proposed mechanism, the positioning of urea in the active site is induced by the structural features of the active site residues which are positioned to act as hydrogen - bond donors in the vicinity of Ni1 and as acceptors in the vicinity of Ni2. The main structural difference between the Ciurli / Mangani mechanism and the other two is that it incorporates a nitrogen, oxygen bridging urea that is attacked by a bridging hydroxide. Action in pathogenesis Bacterial ureases are often the mode of pathogenesis for many medical conditions. They are associated with hepatic encephalopathy / Hepatic coma, infection stones, and peptic ulceration. Infection stones Infection induced urinary stones are a mixture of struvite ( MgNH PO 6H O ) and carbonate apatite ( Ca ( PO ) 6 CO ). These polyvalent ions are soluble but become insoluble when ammonia is produced from microbial urease during urea hydrolysis, as this increases the surrounding environments pH from roughly 6.5 to 9. The resultant alkalinization results in stone crystallization. In humans the microbial urease, Proteus mirabilis, is the most common in infection induced urinary stones. Urease in hepatic encephalopathy / hepatic coma Studies have shown that Helicobacter pylori along with cirrhosis of the liver cause hepatic encephalopathy and hepatic coma. Heliobacter pylori are microbial ureases found in the stomach. As ureases they hydrolyze urea to produce ammonia and carbonic acid. As the bacteria are localized to the stomach ammonia produced is readily taken up by the circulatory system from the gastric lumen. This results in elevated ammonia levels in the blood and is coined as hyperammonemia, eradication of Heliobacter pylori show marked decreases in ammonia levels. Urease in peptic ulcers Helicobacter pylori is also the cause of peptic ulcers with its manifestation in 55 -- 68 % reported cases. This was confirmed by decreased ulcer bleeding and ulcer reoccurrence after eradication of the pathogen. In the stomach there is an increase in pH of the mucosal lining as a result of urea hydrolysis, which prevents movement of hydrogen ions between gastric glands and gastric lumen. In addition, the high ammonia concentrations have an effect on intercellular tight junctions increasing permeability and also disrupting the gastric mucous membrane of the stomach. Environmental significance Urea is found naturally in the environment and is also artificially introduced, comprising more than half of all synthetic nitrogen fertilizers used globally. Heavy use of urea is thought to promote eutrophication, despite the observation that urea is rapidly transformed by microbial ureases, and thus usually does not persist. Environmental urease activity is often measured as an indicator of the health of microbial communities. In the absence of plants, urease activity in soil is generally attributed to heterotrophic microorganisms, although it has been demonstrated that some chemoautotrophic ammonium oxidizing bacteria are capable of growth on urea as a sole source of carbon, nitrogen, and energy. As diagnostic test Main article : Rapid urease 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 : Proteus mirabilis and Proteus vulgaris Ureaplasma urealyticum, a relative of Mycoplasma spp. Nocardia Corynebacterium urealyticum Cryptococcus spp., an opportunistic fungus Helicobacter pylori Certain Enteric bacteria including Proteus spp., Klebsiella spp., Morganella, Providencia, and possibly Serratia spp. Brucella Staphylococcus saprophyticus Extraction First isolated as a crystal in 1926 by Sumner, using acetone solvation and centrifuging. Modern biochemistry has increased its demand for urease. Jack bean meal, watermelon seeds, and pea seeds have all proven useful sources of urease. See also Urea carboxylase Allophanate hydrolase Urease test References Jump up ^ Holm L, Sander C ( 1997 ). `` An evolutionary treasure : unification of a broad set of amidohydrolases related to urease ''. Proteins. 28 ( 1 ) : 72 -- 82. doi : 10.1002 / ( SICI ) 1097 - 0134 ( 199705 ) 28 : 1 < 72 : : AID - PROT7 > 3.0.CO ; 2 - L. PMID 9144792. ^ Jump up to : Zimmer M ( Apr 2000 ). `` Molecular mechanics evaluation of the proposed mechanisms for the degradation of urea by urease ''. J Biomol Struct Dyn. 17 ( 5 ) : 787 -- 97. doi : 10.1080 / 07391102.2000. 10506568. PMID 10798524. ^ Jump up to : Krajewska B, van Eldik R, Brindell M ( 13 August 2012 ). `` Temperature - and pressure - dependent stopped - flow kinetic studies of jack bean urease. Implications for the catalytic mechanism ''. JBIC Journal of Biological Inorganic Chemistry. 17 ( 7 ) : 1123 -- 1134. doi : 10.1007 / s00775 - 012 - 0926 - 8. PMC 3442171. PMID 22890689. Jump up ^ Musculus, `` Sur le ferment de l'urée '', Comptes rendus de l'Académie des sciences, vol. 82, 1876, pp. 333 - 336, reachable in Gallica ^ Jump up to : Karplus PA, Pearson MA, Hausinger RP ( 1997 ). `` 70 years of crystalline urease : What have we learned ? ''. Accounts of Chemical Research. 30 ( 8 ) : 330 -- 337. doi : 10.1021 / ar960022j. Jump up ^ The Nobel Prize in Chemistry 1946 Jump up ^ Anke M, Groppel B, Kronemann H, Grün M ( 1984 ). `` Nickel -- an essential element ''. IARC Sci. Publ. ( 53 ) : 339 -- 65. PMID 6398286. ^ Jump up to : Carter EL, Flugga N, Boer JL, Mulrooney SB, Hausinger RP ( 1 January 2009 ). `` Interplay of metal ions and urease ''. Metallomics. 1 ( 3 ) : 207 -- 21. doi : 10.1039 / b903311d. PMC 2745169. PMID 20046957. ^ Jump up to : Krajewska, Barbara ( 30 June 2009 ). `` Ureases I. Functional, catalytic and kinetic properties : A review ''. Journal of Molecular Catalysis B : Enzymatic. 59 ( 1 -- 3 ) : 9 -- 21. doi : 10.1016 / j. molcatb. 2009.01. 003. ^ Jump up to : Ha NC, Oh ST, Sung JY, Cha KA, Lee MH, Oh BH ( 31 May 2001 ). `` Supramolecular assembly and acid resistance of Helicobacter pylori urease ''. Nature Structural Biology. 8 ( 6 ) : 505 -- 509. doi : 10.1038 / 88563. PMID 11373617. Jump up ^ Strugatsky D, McNulty R, Munson K, Chen CK, Soltis SM, Sachs G, Luecke H ( 8 December 2012 ). `` Structure of the proton - gated urea channel from the gastric pathogen Helicobacter pylori ''. Nature. 493 ( 7431 ) : 255 -- 258. doi : 10.1038 / nature11684. PMC 3974264. PMID 23222544. Jump up ^ Ciurli S, Benini S, Rypniewski WR, Wilson KS, Miletti S, Mangani S ( 1999 ). `` Structural properties of the nickel ions in urease : novel insights into the catalytic and inhibition mechanisms ''. Coordination Chemistry Reviews. 190 -- 192 : 331 -- 355. doi : 10.1016 / S0010 - 8545 ( 99 ) 00093 - 4. ^ Jump up to : Benini S, Rypniewski WR, Wilson KS, Miletti S, Ciurli S, Mangani S ( 31 January 1999 ). `` A new proposal for urease mechanism based on the crystal structures of the native and inhibited enzyme from Bacillus pasteurii : why urea hydrolysis costs two nickels ''. Structure. 7 ( 2 ) : 205 -- 216. doi : 10.1016 / S0969 - 2126 ( 99 ) 80026 - 4. PMID 10368287. ^ Jump up to : Martin PR, Hausinger RP ( Oct 5, 1992 ). `` Site - directed mutagenesis of the active site cysteine in Klebsiella aerogenes urease ''. The Journal of Biological Chemistry. 267 ( 28 ) : 20024 -- 7. PMID 1400317. Jump up ^ Dixon NE, Riddles PW, Gazzola C, Blakeley RL, Zerner B ( 1979 ). `` Jack Jack Bean Urease ( EC3. 5.1. 5 ). V. On the Mechanism of action of urease on urea, formamide, acetamide, N - methylurea, and related compounds ''. Canadian Journal of Biochemistry. 58 ( 12 ) : 1335 -- 1344. doi : 10.1139 / o80 - 181. PMID 6788353. Jump up ^ Jabri E, Carr MB, Hausinger RP, Karplus PA ( May 19, 1995 ). `` The crystal structure of urease from Klebsiella aerogenes ''. Science. 268 ( 5213 ) : 998 -- 1004. doi : 10.1126 / science. 7754395. PMID 7754395. Jump up ^ Zambelli B, Musiani F, Benini S, Ciurli S ( 19 July 2011 ). `` Chemistry of Ni2+ in Urease : Sensing, Trafficking, and Catalysis ''. Accounts of Chemical Research. 44 ( 7 ) : 520 -- 530. doi : 10.1021 / ar200041k. PMID 21542631. ^ Jump up to : Mobley HL, Hausinger RP ( March 1989 ). `` Microbial ureases : significance, regulation, and molecular characterization ''. Microbiological Reviews. 53 ( 1 ) : 85 -- 108. PMC 372718. PMID 2651866. Jump up ^ Rosenstein IJ ( 1 January 1986 ). `` Urinary Calculi : Microbiological and Crystallographic Studies ''. Critical Reviews in Clinical Laboratory Sciences. 23 ( 3 ) : 245 -- 277. doi : 10.3109 / 10408368609165802. PMID 3524996. ^ Jump up to : Agrawal A, Gupta A, Chandra M, Koowar S ( 17 March 2011 ). `` Role of Helicobacter pylori infection in the pathogenesis of minimal hepatic encephalopathy and effect of its eradication ''. Indian Journal of Gastroenterology. 30 ( 1 ) : 29 -- 32. doi : 10.1007 / s12664 - 011 - 0087 - 7. PMID 21416318. ^ Jump up to : Tang JH, Liu NJ, Cheng HT, Lee CS, Chu YY, Sung KF, Lin CH, Tsou YK, Lien JM, Cheng CL ( February 2009 ). `` Endoscopic diagnosis of Helicobacter pylori infection by rapid urease test in bleeding peptic ulcers : a prospective case - control study ''. Journal of Clinical Gastroenterology. 43 ( 2 ) : 133 -- 9. doi : 10.1097 / MCG. 0b013e31816466ec. PMID 19230239. Jump up ^ Caron, Tyler ( 2015 ). `` Tight junction disruption : Helicobacter pylori and dysregulation of the gastric mucosal barrier ''. World J Gastroenterol. 21 ( 40 ) : 11411 -- 11427. doi : 10.3748 / wjg. v21. i40. 11411. Jump up ^ Glibert P, Harrison J, Heil C, Seitzinger S ( 2006 ). `` Escalating worldwide use of urea -- a global change contributing to coastal eutrophication ''. Biogeochemistry. 77 : 441 -- 463. doi : 10.1007 / s10533 - 005 - 3070 - 5. Jump up ^ Daigh AL, Savin MC, Brye K, Norman R, Miller D ( 2014 ). `` Urea persistence in floodwater and soil used for flooded rice production ''. Soil Use and Management. 30 ( 4 ) : 463 -- 470. doi : 10.1111 / sum. 12142. Jump up ^ Marsh, K.L., G.K. Sims, and R.L. Mulvaney. 2005. Availability of urea to autotrophic ammonia - oxidizing bacteria as related to the fate of 14C - and 15N - labeled urea added to soil. Biol. Fert. Soil. 42 : 137 - 145. Jump up ^ Gorin, G ; Butler, M.F. ; Katyal, J.M. ; Buckley, J.E. ( 1959 ). `` Isolation of Crystalline Urease '' ( PDF ). proceedings of the Oklahoma Academy of Sciences. Retrieved Dec 7, 2014. Jump up ^ Sung HY, Lee WM, Chiou MJ, Chang CT ( Oct 13, 1989 ). `` procedure for purifying jack bean urease for clinical use ''. Proc Natl Sci Counc Repub China B. 13 ( 4 ) : 250 -- 7. PMID 2517764. Jump up ^ Prakash, O ; Brushan, G ( Jan 1, 1997 ). `` Isolation, purification and partial characterisation of urease from seeds of water melon ( Citrullus vulgaris ) ''. Journal of Plant Biochemistry and Biotechnology. 6 : 45 -- 47. doi : 10.1007 / BF03263009. Jump up ^ El - Hefnawy ME, Sakran M, Ismail AI, Aboelfetoh EF ( 2014 ). `` Extraction, purification, kinetic and thermodynamic properties of urease from germinating Pisum Sativum L. seeds ''. BMC Biochemistry. 15 ( 1 ) : 15. doi : 10.1186 / 1471 - 2091 - 15 - 15. PMC 4121304. PMID 25065975. External links Mobley HL ( 2001 ). `` Chapter 16 : Urease ''. In Mobley HL, Mendz GL, Hazell SL. Helicobacter pylori : Physiology and Genetics. Washington ( DC ) : ASM Press. ISBN 1 - 55581 - 213 - 9. PMID 21290719. Hydrolases : carbon - nitrogen non-peptide ( EC 3.5 ) 3.5. 1 : Linear amides / Amidohydrolases Asparaginase Glutaminase Urease Biotinidase Aspartoacylase Ceramidase Aspartylglucosaminidase Fatty acid amide hydrolase Histone deacetylase Sirtuin 3.5. 2 : Cyclic amides / Amidohydrolases Barbiturase Beta - lactamase 3.5. 3 : Linear amidines / Ureohydrolases Arginase Agmatinase Protein - arginine deiminase 3.5. 4 : Cyclic amidines / Aminohydrolases Guanine deaminase Adenosine deaminase AMP deaminase Inosine monophosphate synthase DCMP deaminase GTP cyclohydrolase I Cytidine deaminase AICDA Activation - induced cytidine deaminase 3.5. 5 : Nitriles / Aminohydrolases Nitrilase 3.5. 99 : Other Riboflavinase Thiaminase II Enzymes Activity Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Catalytically perfect enzyme Coenzyme Cofactor Enzyme catalysis Regulation Allosteric regulation Cooperativity Enzyme inhibitor Classification EC number Enzyme superfamily Enzyme family List of enzymes Kinetics Enzyme kinetics Eadie -- Hofstee diagram Hanes -- Woolf plot Lineweaver -- Burk plot Michaelis -- Menten kinetics Types EC1 Oxidoreductases ( list ) EC2 Transferases ( list ) EC3 Hydrolases ( list ) EC4 Lyases ( list ) EC5 Isomerases ( list ) EC6 Ligases ( list ) Molecular and Cellular Biology portal Retrieved from `` https://en.wikipedia.org/w/index.php?title=Urease&oldid=813170484 '' Categories : Nickel enzymes EC 3.5. 1 Talk Search Contents About Wikipedia Bosanski Català Cymraeg Dansk Deutsch Español Euskara فارسی Français Galego 한국어 Italiano עברית Latviešu Nederlands 日本 語 Polski Português Русский Српски / srpski Srpskohrvatski / српскохрватски Suomi Svenska தமிழ் Українська 中文 Edit links This page was last edited on 2 December 2017, at 05 : 41. Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: to what class of enzymes does urease belong
Answer: metalloenzymes