Properties of urease from <i>Ureaplasma urealyticum</i>: kinetics, molecular weight, and demonstration of multiple enzyme isoelectric point forms

H, Eng; Robertson, Janet A.; Stemke, Gerald W.

doi:10.1139/m86-089

Cited by 26 publications

(11 citation statements)

References 27 publications

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“…However, multiple pIs are not an uncommon biochemical finding, particularly after electrochemical separation. Multiple enzyme isoelectric point forms in the urease of the Mollicutes U. urealyticum have been reported (Eng et al, 1986). Although our finding indicates that there are multiple forms of the AK enzyme in our preparations, this is not convincing evidence of naturally occurring isoenzymes.…”

Section: Discussioncontrasting

confidence: 66%

Suspected Utility of Enzymes with Multiple Activities in the Small GenomeMycoplasmaSpecies: The Replacement of the Missing "Household" Nucleoside Diphosphate Kinase Gene and Activity by Glycolytic Kinases

Pollack

Myers

Dandekar

et al. 2002

OMICS: A Journal of Integrative Biology

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The small genome Mollicutes whose DNAs are completely sequenced (Mycoplasma genitalium, Mycoplasma pneumoniae, Mycoplasma pulmonis, and Ureaplasma urealyticum [parvum]) lack a gene (ndk) for the presumably essential nucleoside diphosphate kinase (NDPK). We hypothesized that other activities might replace NDPK activity. We found in M. genitalium G37(T), Mycoplasma pneumoniae FH(T), Mycoplasma fermentans PG18(T), and Mycoplasma capricolum subsp. capricolum Kid(T) that their 6-phosphofructokinases (6-PFKs), phosphoglycerate kinases (PGKs), pyruvate kinases (PKs), and acetate kinases (AKs), besides reactant ADP/ATP, could use other ribo- and deoxyribo-purine and pyrimidine NDPs and NTPs. These activities could compensate for the absence of an orthologous ndk gene in the Mycoplasmataceae. They suggest a metabolically varied and consequential role for unrelated and perhaps unsuspected "replacement" or compensatory enzymes that may confound metabolic prediction. We partially purified and biochemically characterized the PKs, 6-PFKs, PGKs, and AKs from M. capricolum subsp. capricolum Kid(T) and M. fermentans PG18(T).

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Section: Discussioncontrasting

confidence: 66%

Suspected Utility of Enzymes with Multiple Activities in the Small GenomeMycoplasmaSpecies: The Replacement of the Missing "Household" Nucleoside Diphosphate Kinase Gene and Activity by Glycolytic Kinases

Pollack

Myers

Dandekar

et al. 2002

OMICS: A Journal of Integrative Biology

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“…In addition, this genetic variation, in particular Comparison of urease genes from serotypes 1 and 8 showed minor differences. In particular, the deduced UreB and UreC polypeptides from serotype 1 have a lower molecular weight than those of serotype 8, this finding concurring with the difference previously observed by gel electrophoresis of the ureases from these serotypes (18).…”

Section: Discussionsupporting

confidence: 90%

Organization of Ureaplasma urealyticum urease gene cluster and expression in a suppressor strain of Escherichia coli

et al. 1996

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Ureaplasma urealyticum is a pathogenic ureolytic mollicute which colonizes the urogenital tracts of humans. A genetic polymorphism between the two biotypes of U. urealyticum at the level of the urease genes was found. The urease gene cluster from a biotype 1 representative of U. urealyticum (serotype 1) was cloned and sequenced. Seven genes were found, with ureA, ureB, and ureC encoding the structural subunits and ureE, ureF, ureG, and a truncated ureD gene encoding accessory proteins. Urease expression was not obtained when the plasmid containing these genes was incorporated into an opal suppressor strain of Escherichia coli, although this enzymatic activity was found in the same E. coli strain transformed with pC6b, a plasmid with previously cloned urease genes from the U. urealyticum T960 strain of biotype 2 (serotype 8). Although there are 12 TGA triplets encoding tryptophan within urease genes, the level of expression obtained was comparable to the levels reported for other bacterial genes expressed in E. coli. Nested deletion experiments allowed us to demonstrate that ureD is necessary for urease activity whereas another open reading frame located downstream is not. The promoter for ureA and possibly other urease genes was identified for both serotypes.Members of the class Mollicutes (trivial name, mycoplasmas) are wall-less prokaryotes that have been characterized as the smallest self-replicating organisms (34). In humans, mycoplasmas colonize mucosal surfaces and identified pathogens include species from the genera Mycoplasma and Ureaplasma.The 14 serotypes of Ureaplasma urealyticum that colonize the human species can be clustered into two biotypes (36). This species has been implicated in various diseases including urethritis, septic arthritis, urinary stone formation, and various infections of premature babies and pregnant women (7-9). It seems that strains from the two biotypes could have different pathogenic potentials, but an association between a specific disease and a biotype remains to be demonstrated (20,31,37).The genus Ureaplasma is differentiated from the class Mollicutes by the production of urease (urea amidohydrolase), which hydrolyzes urea into ammonia and carbamic acid. In the presence of water, carbamic acid is cleaved to ammonia and carbonic acid, which results in an increase in pH. U. urealyticum lacks the conventional pathways for ATP production (glycolysis and arginine breakdown) which are present in the other species of mycoplasmas. Growth is inhibited by specific urease inhibitors and is dependent on urea (24), indicating that there is a major role for urease in the metabolism of ureaplasmas. It has also been demonstrated that urea hydrolysis is coupled to ATP synthesis (38) and generates an ammonium ion transmembrane gradient that could be used to activate an ATP synthetase, F 1 F 0 ATPase (40). In addition to this key role in ureaplasmal metabolism, urease also contributes to the pathogenic potential of the ureaplasmas.The increase of extracellular pH associated with urea hydrol...

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“…A single form was observed for Bacillus pasteur/ii and Brei'ibacteeriun t amninoia genes ureases at pl values of 4.6 and 4.1, respectively (37,167). In contrast, four bands were observed (pl, 4.3 to 4.7) for Arthlobacter oxvdans urease (204) and two or three bands (pl, 5.0 to 5.2) for the cell extracts from U. urealyticuin (47,199). In addition, analysis of cell extracts from Morganella morganii, Proteuts mnir-abilis, Protelus i'ulgaris, Proi,iclencia rettgeri, and Prol'idencia stluaIr'tii (97) revealed that each species possessed a major form of urease (pl, 5.1 to 5.9) and at least one secondary form.…”

Section: )mentioning

confidence: 92%

Microbial ureases: significance, regulation, and molecular characterization.

Mobley¹,

Hausinger²

1989

Microbiological Reviews

847

538

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Properties of urease from Ureaplasma urealyticum: kinetics, molecular weight, and demonstration of multiple enzyme isoelectric point forms

Cited by 26 publications

References 27 publications

Suspected Utility of Enzymes with Multiple Activities in the Small GenomeMycoplasmaSpecies: The Replacement of the Missing "Household" Nucleoside Diphosphate Kinase Gene and Activity by Glycolytic Kinases

Suspected Utility of Enzymes with Multiple Activities in the Small GenomeMycoplasmaSpecies: The Replacement of the Missing "Household" Nucleoside Diphosphate Kinase Gene and Activity by Glycolytic Kinases

Organization of Ureaplasma urealyticum urease gene cluster and expression in a suppressor strain of Escherichia coli

Microbial ureases: significance, regulation, and molecular characterization.

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