Purine base transport in wild-type and mycophenolic acid-resistant Tritrichomonas foetus.
The purine base transport systems of wild-type and mycophenolic acid-resistant (MPAR) Tritrichomonas foetus have been characterized. Wild-type T. foetus has two carriers, one for hypoxanthine (Km = 0.7 +/- 0.3 mM, Vm = 80 +/- 20 pmol microliters-1min-1) and guanine (Km = 0.09 +/- 0.02 mM, Vm = 17 +/- 3 pmol microliters-1min-1), and a second for xanthine (Km = 0.6 +/- 0.2 mM, Vm = 25 +/- 5 pmol microliters-1min-1). Adenine transport was not saturable (k = 0.16 +/- 0.01 min-1) and therefore appears to enter the parasite by passive diffusion through the membrane. T. foetus MPAR has lost the hypoxanthine/guanine transporter. Xanthine and adenine transport are similar in wild-type and MPAR T. foetus. No purine nucleoside transporter could be identified.
Hedstrom
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Department of Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco.
Wang
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D000225:Adenine / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology; D000493:Allopurinol / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D004058:Diffusion; D004351:Drug Resistance; D006147:Guanine / Q000378:metabolism / Q000494:pharmacology; D007042:Hypoxanthines / Q000378:metabolism; D007700:Kinetics; D009173:Mycophenolic Acid / Q000494:pharmacology*; D011684:Purine Nucleosides / Q000378:metabolism; D011687:Purines / Q000378:metabolism*; D014318:Tritrichomonas / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D014970:Xanthines / Q000378:metabolism / Q000494:pharmacology
D007042:Hypoxanthines; D011684:Purine Nucleosides; D011687:Purines; D014970:Xanthines; D006147:Guanine; D000493:Allopurinol; D009173:Mycophenolic Acid; D000225:Adenine