title: Modulation of Trypanosoma rangeli ecto-phosphatase activity by hydrogen peroxide.
abstract: As a protozoan parasite of hematophagous insects, Trypanosoma rangeli epimastigotes are exposed to reactive oxygen species during development in hosts. In this work, we investigated the role of H(2)O(2) as a modulator of the ecto-phosphatase activity present in living T. rangeli. We observed that H(2)O(2) inhibits ecto-phosphatase activities in the short and long epimastigote forms of T. rangeli. Ecto-phosphatase activity found in the short form was more sensitive than that found in the long form. Moreover, H(2)O(2) inhibited ecto-phosphatase activity of the short form in a dose-dependent manner and this inhibition was reversible after H(2)O(2) removal. This effect was not observed for T. rangeli ecto-ATPase, another ecto-enzyme present on the external surface of T. rangeli. Cysteine, beta-mercaptoethanol, and reduced glutathione were able to revert the enzyme inhibition promoted by H(2)O(2). Catalase and glutathione peroxidase stimulated this ecto-phosphatase activity, whereas superoxide dismutase was not able to modulate this activity. The ecto-phosphatase activity was also activated by FCCP and inhibited by oligomycin. It seems that H(2)O(2) plays a fundamental role in the regulation of cellular processes of these organisms. We showed, for the first time, that these parasites can produce H(2)O(2), and it is able to regulate ecto-phosphatase activity.
authors.affiliation: Instituto de Bioquímica Médica and Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Ilha do Fundão, 21941-590 Rio de Janeiro, RJ, Brazil.
authors.forename: Daniela
authors.initials: D
authors.lastname: Cosentino-Gomes
authors.forename: Thais
authors.initials: T
authors.lastname: Russo-Abrahão
authors.forename: André Luiz
authors.initials: AL
authors.lastname: Fonseca-de-Souza
authors.forename: Clara Rodrigues
authors.initials: CR
authors.lastname: Ferreira
authors.forename: Antonio
authors.initials: A
authors.lastname: Galina
authors.forename: José Roberto
authors.initials: JR
authors.lastname: Meyer-Fernandes
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D002374:Catalase / Q000494:pharmacology; D003545:Cysteine / Q000494:pharmacology; D004789:Enzyme Activation; D005979:Glutathione Peroxidase / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000378:metabolism* / Q000494:pharmacology; D008623:Mercaptoethanol / Q000494:pharmacology; D009840:Oligomycins / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*; D015800:Protozoan Proteins / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000494:pharmacology; D014345:Trypanosoma / Q000201:enzymology*
chemical_list: D009840:Oligomycins; D015800:Protozoan Proteins; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D008623:Mercaptoethanol; D006861:Hydrogen Peroxide; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D010749:Phosphoprotein Phosphatases; D000251:Adenosine Triphosphatases; D003545:Cysteine