title: Characterization of the inorganic pyrophosphatase from the pathogenic bacterium Helicobacter pylori.
abstract: A cytoplasmic pyrophosphatase [E.C. 3.6.1.1.] was partially purified from Helicobacter pylori. The molecular mass was estimated to be 103 kDa by gel filtration. Results of SDS-PAGE suggested that the enzyme consists of six identical subunits of 19.1 kDa each. The enzyme specifically catalyzed the hydrolysis of pyrophosphate and was very sensitive to NaF, but not to sodium molybdate. The optimal pH for activity was 8.5. Mg2+ was required for maximal activity; Mn2+, Co2+, and Zn2+ poorly supported hydrolytic activity. The pyrophosphatase had an apparent K(m) for Mg-PP(i)2 hydrolysis of 90 microM, and a Vmax estimated at 24.0 micromol P(i) min(-1) mg(-1).
authors.affiliation: Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, D.F., Mexico.
authors.forename: G
authors.initials: G
authors.lastname: Oliva
authors.forename: I
authors.initials: I
authors.lastname: Romero
authors.forename: G
authors.initials: G
authors.lastname: Ayala
authors.forename: I
authors.initials: I
authors.lastname: Barrios-Jacobo
authors.forename: H
authors.initials: H
authors.lastname: Celis
mesh_terms: D000595:Amino Acid Sequence; D002413:Cations, Divalent / Q000378:metabolism; D003593:Cytoplasm / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016480:Helicobacter pylori / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D043564:Inorganic Pyrophosphatase; D007700:Kinetics; D008970:Molecular Weight; D021122:Protein Subunits; D011755:Pyrophosphatases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D002413:Cations, Divalent; D004791:Enzyme Inhibitors; D021122:Protein Subunits; D011755:Pyrophosphatases; D043564:Inorganic Pyrophosphatase