Pizauro, J. M.Ciancaglini, P.Leone, F. A.2014-05-202014-05-201993-09-03Biochimica Et Biophysica Acta. Amsterdam: Elsevier B.V., v. 1202, n. 1, p. 22-28, 1993.0006-3002http://hdl.handle.net/11449/32220Alkaline phosphatase from rat osseous plate is allosterically modulated by ATP, calcium and magnesium at pH 7.5. At pH 9.4, the hydrolysis of ATP and PNPP follows Michaelis-Menten kinetics with K0.5 values of 154 muM and 42 muM, respectively. However, at pH 7.5 both substrates exhibit more complex saturation curves, while only ATP exhibited site-site interactions. Ca2+-ATP and Mg2+-ATP were effective substrates for the enzyme, while the specific activity of the enzyme for the hydrolysis of ATP at pH 7.5 was 800-900 U/mg and was independent of the ion species. ATP, but not PNPP, was hydrolyzed slowly in the absence of metal ions with a specific activity of 140 U/mg. These data demonstrate that in vitro and at pH 7.5 rat osseous plate alkaline phosphatase is an active calcium or magnesium-activated ATPase.22-28engALLOSTERIC MODULATIONAlkaline phosphataseATPaseENZYME KINETICSArtigo10.1016/0167-4838(93)90058-YWOS:A1993LY16100004Acesso restrito