title: An ectonucleotide ATP-diphosphohydrolase activity in Trichomonas vaginalis stimulated by galactose and its possible role in virulence.
abstract: This work describes the ability of living Trichomonas vaginalis to hydrolyze extracellular ATP (164.0 +/- 13.9 nmol Pi/h x 10(7) cells). This ecto-enzyme was stimulated by ZnCl2, CaCl2 and MgCl2, was insensitive to several ATPase and phosphatase inhibitors and was able to hydrolyze several nucleotides besides ATP. The activity was linear with cell density and with time for at least 60 min. The optimum pH for the T. vaginalis ecto-ATPase lies in the alkaline range. D-galactose, known to be involved in adhesion of T. vaginalis to host cells, stimulated this enzyme by more than 90%. A comparison between two strains of T. vaginalis showed that the ecto-ATPase activity of a fresh isolate was twice as much as that of a strain axenically maintained in culture, through daily passages, for several years. The results suggest a possible role for this ecto-ATPase in adhesion of T. vaginalis to host cells and in its pathogenicity.
authors.affiliation: Departamento de Bioquímica Médica, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Cidad Universitária, RJ, Brazil.
authors.forename: José Batista
authors.initials: JB
authors.lastname: de Jesus
authors.forename: Ana Acacia
authors.initials: AA
authors.lastname: de Sá Pinheiro
authors.forename: Angela H C S
authors.initials: AH
authors.lastname: Lopes
authors.forename: José Roberto
authors.initials: JR
authors.lastname: Meyer-Fernandes
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D001081:Apyrase / Q000378:metabolism*; D002122:Calcium Chloride / Q000494:pharmacology; D002712:Chlorides / Q000494:pharmacology; D004789:Enzyme Activation; D005690:Galactose / Q000494:pharmacology*; D007700:Kinetics; D015636:Magnesium Chloride / Q000494:pharmacology; D012265:Ribonucleotides / Q000378:metabolism; D013379:Substrate Specificity; D014246:Trichomonas vaginalis / Q000201:enzymology* / Q000472:pathogenicity*; D017967:Zinc Compounds / Q000494:pharmacology
chemical_list: D002712:Chlorides; D012265:Ribonucleotides; D017967:Zinc Compounds; D015636:Magnesium Chloride; C016837:zinc chloride; D000251:Adenosine Triphosphatases; C027201:ectoATPase; D001081:Apyrase; D002122:Calcium Chloride; D005690:Galactose