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Uptake of pentamidine in Trypanosoma brucei brucei is mediated by the P2 adenosine transporter and at least one novel, unrelated transporter

de Koning, Harry P. and Jarvis, Simon M. (2001) Uptake of pentamidine in Trypanosoma brucei brucei is mediated by the P2 adenosine transporter and at least one novel, unrelated transporter. Acta Tropica, 80 (3). pp. 245-250. ISSN 0001-706X

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Official URL: http://dx.doi.org/10.1016/S0001-706X(01)00177-2

Abstract

Diamidine drugs such as pentamidine and berenil (diminazene aceturate) are vital drugs for the treatment of early stage human African trypanosomiasis and the corresponding veterinary condition, respectively. The action of diamidines on trypanosomes is critically dependent on their efficient uptake by the parasite. We have therefore investigated the mode of uptake of pentamidine by Trypanosoma brucei brucei, using [125I]iodopentamidine as a permeant. [125I]Iodopentamidine uptake was linear for up to 15 min and inhibited by adenosine with a Ki value of 0.64±0.03 μM, to a maximum of 50-70%. The adenosine-sensitive flux was also inhibited by adenine with a Ki value of 0.44±0.04 μMM. Iodopentamidine uptake was saturable, with the adenosine-insensitive flux displaying a Km of 22±2 μM and a Vmax of 2.2±0.9 pmol(107 cells)−1 s−1, whereas the adenosine-sensitive flux was inhibited by much lower iodopentamidine concentrations. These results clearly demonstrate that iodopentamidine is taken up by at least two different T. b. brucei transporters, an adenosine-sensitive pentamidine transporter (ASPT1) and a low-affinity pentamidine transporter (LAPT1). The identity of these transporters was investigated, and their significance for drug uptake and resistance in African trypanosomes is discussed.

Item Type:Article
Additional Information:Online ISSN 0365-1541
Uncontrolled Keywords:Pentamidine, Trypanosoma brucei, Drug uptake, P2 transporter
Research Community:University of Westminster > Life Sciences, School of
ID Code:287
Deposited On:30 Aug 2005
Last Modified:12 Oct 2009 16:32

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