title: Inorganic pyrophosphatase activity in cell-free extracts of Ureaplasma urealyticum.
abstract: Cell-free extracts of Ureaplasma urealyticum strains Pi and T960 (CX8) (serovars 6 and 8, respectively) metabolized inorganic pyrophosphate (PPi). The inorganic pyrophosphatase (PPase) activity was greatest with Mg2+ as cofactor, but Mn2+ acted as a poor substitute. The PPases of the two serovars differed electrophoretically. Although the highest PPase activity was obtained using PPi as substrate, the enzyme could also utilize to a lesser degree both tripolyphosphate and trimetaphosphate. No activity was observed against beta-glycerophosphate, naphthyl phosphates, glucose 6-phosphate, fructose 6-phosphate, fructose 1,6-bisphosphate, thiamin pyrophosphate, phosphoribosylpyrophosphate, ADP or ATP. Acid- and alkaline-phosphatase activities were observed with naphthyl phosphates as substrates, but they did not have the same electrophoretic mobility on gels as the PPase activity. U. urealyticum PPase was inhibited by oxidized glutathione, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, phenylglyoxal, p-chloromercuribenzoic acid, Mn2+, Zn2+ and Ca2+. Neither reduced glutathione, L-cysteine nor Co2+ enhanced activity. PPi can act as a substrate or regulator of certain metabolic reactions, and PPi metabolism can function in bacterial bioenergetics; its role in ureaplasmas is presently unclear.
authors.affiliation: Department of Biology and Medical Laboratory Technology, Bronx Community College of the City University of New York, Bronx 10453.
authors.forename: J W
authors.initials: JW
authors.lastname: Davis
authors.forename: I S
authors.initials: IS
authors.lastname: Moses
authors.forename: C
authors.initials: C
authors.lastname: Ndubuka
authors.forename: R
authors.initials: R
authors.lastname: Ortiz
mesh_terms: D002413:Cations, Divalent / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D011755:Pyrophosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014509:Ureaplasma / Q000201:enzymology*
chemical_list: D002413:Cations, Divalent; D004791:Enzyme Inhibitors; D011755:Pyrophosphatases