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dc.contributor.authorRezende, L. A.
dc.contributor.authorCiancaglini, P.
dc.contributor.authorPizauro, J. M.
dc.contributor.authorLeone, F. A.
dc.identifier.citationCellular and Molecular Biology. Noisy-le-grand: Cellular & Molecular Biology, v. 44, n. 2, p. 293-302, 1998.
dc.description.abstractPurified membrane-bound alkaline phosphatase from rat osseous plate hydrolyzed pyrophosphate in the presence of magnesium ions, with a specific activity of 92.7 U/mg. Optimal apparent pH for pyrophosphatase activity was 8.0 and it remained unchanged on increasing the pyrophosphate concentration. In the absence of magnesium ions the enzyme had a K-m = 88 mu M and V = 36.7 U/mg for pyrophosphate and no inhibition by excess substrate was observed. Pyrophosphatase activity was rapidly destroyed at temperatures above 40 degrees C, but magnesium ions apparently protected the enzyme against danaturation. Sodium metavanadate (Ki = 1.0 mM) was a competitive inhibitor of pyrophosphatase activity, while levamisole (Ki = 8.2 mM) and theophylline (Ki = 7.4 mM) were uncompetitive inhibitors. Magnesium ions (K-0.5 = 1.7 mu M) stimulated pyrophosphatase activity, while cobalt (Ki = 48.5 mu M) and zinc (Ki = 22.0 mu M) ions were non-competitive inhibitors. Manganese and calcium ions had no effect on pyrophosphatase activity. The M-w of the pyrophosphatase: protein was 130 kDa by gel filtration, but a value of 65 kDa was obtained by dissociative gel electrophoresis, suggesting that it was a dimer of apparently identical subunits. These results suggested that pyrophosphatase activity stems from the membrane-bound osseous plate alkaline phosphatase and not from a different protein.en
dc.publisherCellular & Molecular Biology
dc.relation.ispartofCellular and Molecular Biology
dc.sourceWeb of Science
dc.subjectAlkaline phosphatasept
dc.subjectOsseous platept
dc.subjectdivalent ionspt
dc.subjectthermal inactivationpt
dc.titleInorganic pyrophosphate-phosphohydrolytic activity associated with rat osseous plate alkaline phosphataseen
dcterms.rightsHolderCellular & Molecular Biology
dc.contributor.institutionUniversidade de São Paulo (USP)
dc.contributor.institutionUniversidade Estadual Paulista (UNESP)
dc.description.affiliationUSP, Fac Filosofia Ciências & Letras Ribeirao Pret, Dept Quim, BR-14040901 Ribeirao Preto, SP, Brazil
dc.description.affiliationUNESP, Fac Ciências Agrarias & Vet, Dept Tecnol, Jaboticabal, SP, Brazil
dc.description.affiliationUnespUNESP, Fac Ciências Agrarias & Vet, Dept Tecnol, Jaboticabal, SP, Brazil
dc.rights.accessRightsAcesso restrito
unesp.campusUniversidade Estadual Paulista (UNESP), Faculdade de Ciências Agrárias e Veterinárias, Jaboticabalpt[2]
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