Leishmania amazonensis: characterization of an ecto-phosphatase activity.

dc.creatorAmaral, Elmo Eduardo de Almeida
dc.creatorFirpo, Rodrigo Belmont
dc.creatorSantos, Marcos André Vannier dos
dc.creatorFernandes, José Roberto Meyer
dc.date2015-09-29T17:21:49Z
dc.date2015-09-29T17:21:49Z
dc.date2006
dc.date.accessioned2023-09-26T20:52:51Z
dc.date.available2023-09-26T20:52:51Z
dc.identifierAMARAL, E. E. A. et al. Leishmania amazonensis: characterization of an ecto-phosphatase activity. Experimental Parasitology, v. 114, n. 4, p. 334-340, 2006.
dc.identifier0014-4894
dc.identifierhttps://www.arca.fiocruz.br/handle/icict/11846
dc.identifier10.1016/j.exppara.2006.04.011
dc.identifier.urihttps://repositorioslatinoamericanos.uchile.cl/handle/2250/8865507
dc.descriptionWe have characterized a phosphatase activity present on the external surface of Leishmania amazonensis, using intact living parasites. This enzyme hydrolyzes the substrate p-nitrophenylphosphate (p-NPP) at the rate of 25.70§1.17nmol Pi£h¡1£10¡7 cells. The dependence on p-NPP concentration shows a normal Michaelis–Menten kinetics for this ecto-phosphatase activity present a Vmax of 31.93§3.04nmol Pi£h¡1£10¡7 cells and apparent Km of 1.78§0.32mM. Inorganic phosphate inhibited the ecto-phoshatase activity in a dose-dependent manner with the Ki value of 2.60mM. Experiments using classical inhibitor of acid phosphatase, such as ammonium molybdate, as well as inhibitors of phosphotyrosine phosphatase, such as sodium orthovanadate and [potassiumbisperoxo(1,10-phenanthroline) oxovanadate(V)] (bpV-PHEN), inhibited the ecto-phosphatase activity, with the Ki values of 0.33 M, 0.36 M and 0.25 M, respectively. Zinc chloride, another classical phosphotyrosine phosphatase inhibitor, also inhibited the ecto-phosphatase activity in a dose-dependent manner with Ki 2.62mM. Zinc inhibition was reversed by incubation with reduced glutathione (GSH) and cysteine, but not serine, showing that cysteine residues are important for enzymatic activity. Promastigote growth in a medium supplemented with 1mM sodium orthovanadate was completely inhibited as compared to the control medium. Taken together, these results suggest that L. amazonensis express a phosphohydrolase ectoenzyme with phosphotyrosine phosphatase activity. © 2006 Elsevier Inc. All rights reserved.
dc.formatapplication/pdf
dc.languageeng
dc.publisherElsevier
dc.rightsopen access
dc.subjectLeishmania amazonensis
dc.subjectEcto-phosphatase activity
dc.subjectPhosphotyrosine phosphatase
dc.subjectLeishmania mexicana/enzimologia
dc.subjectMonoéster Fosfórico Hidrolases/antagonistas & inibidores
dc.subjectMonoéster Fosfórico Hidrolases/metabolismo
dc.subjectVanadatos/farmacologia
dc.subjectAnimais
dc.subjectCloretos/farmacologia
dc.subjectCisteína/farmacologia
dc.subjectHidrólise/efeitos de drogas
dc.subjectHumanos
dc.subjectCinética
dc.subjectLeishmania mexicana/efeitos de drogas
dc.subjectLeishmania mexicana/crescimento & desenvolvimento
dc.subjectMolibdênio/farmacologia
dc.subjectNitrofenóis/metabolismo
dc.subjectCompostos Organometálicos/farmacologia
dc.subjectFenantrolinas/farmacologia
dc.subjectFosfatos/farmacologia
dc.subjectCompostos de Zinco/farmacologia
dc.titleLeishmania amazonensis: characterization of an ecto-phosphatase activity.
dc.typeArticle


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