title: Putrescine transport system in Leishmania infantum promastigotes.
abstract: A transport system for putrescine in Leishmania infantum (= L. donovani infantum) promastigotes has been identified and characterized by measuring the uptake of radioactively labelled putrescine. Putrescine uptake was time- and temperature-dependent without any accumulation taking place at 0 degrees C. Uptake of putrescine was maximal at pH values near neutrality. Putrescine uptake showed an apparent Km = 1.08 +/- 0.12 microM and a Vmax = 1.74 + 0.62 pmol min-1 (10(6) cells)-1. The effect of metabolic poisons and uncoupling agents suggests that the putrescine uptake was energy-dependent. The transport system seemed to be highly specific for putrescine as neither aminoacids nor related compounds tested showed any competition with putrescine uptake. The trypanocide Berenil inhibited almost completely the putrescine uptake with non-competitive kinetics and a value of Ki = 43 microM.
authors.affiliation: Departamento de Farmacología y Toxicología, Facultad de Veterinaria, Universidad Complutense de Madrid, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Balaña-Fouce
authors.forename: D
authors.initials: D
authors.lastname: Ordóñez
authors.forename: J M
authors.initials: JM
authors.lastname: Alunda
mesh_terms: D000596:Amino Acids / Q000494:pharmacology; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D004133:Diminazene / Q000031:analogs & derivatives / Q000494:pharmacology; D000518:Eflornithine / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007893:Leishmania donovani / Q000187:drug effects / Q000378:metabolism*; D011073:Polyamines / Q000493:pharmacokinetics / Q000494:pharmacology; D011700:Putrescine / Q000493:pharmacokinetics*; D013696:Temperature
chemical_list: D000596:Amino Acids; D011073:Polyamines; C003915:diminazene aceturate; D011700:Putrescine; D004133:Diminazene; D000518:Eflornithine