Pediococcus cerevisiae mutant with altered transport of folates.
A Pediococcus cerevisiae mutant that actively accumulated folate (PteGlu), in contrast to the wild-type, was also found to exhibit changes in the pattern of uptake of 5-methyl-tetrahydrofolate (5-CH3-H4PteGlu) and amethopterin. Most of the 5-CH3-H4PteGlue accumulated through a glucose- and temperature-dependent process, and a concentrative uptake was also found in gluocse-starved cells and in cells incubated at OC. About 75% of the accumulated 5-CH3-H4PteGlu exchanged with amethopterin. In contrast to the wild type, the mutant accumulated both diastereoisomers of 5-CH3-H4PteGlue by glucose-dependent and glucose-independent processes. Amethopterin and PteGlue competitively inhibited the uptake in both processes, with an apparent lower affinity of the carrier for PteGlu than for the analogue. p-Chloromercuribenzoate strongly inhibited the uptake (75%). The p-chloromercuribenzoate-nonsusceptible and temperature-independent uptake was also competed by amethopterin. Metabolic poisons like sodium azide, potassium fluoride, iodoacetate, and 2,4-dimitrophenol inhibited the glucose-dependent process. Uptake, in the absence of glucose, was enhanced by sodium azide and potassium fluoride.
D001386:Azides / Q000494:pharmacology; D001667:Binding, Competitive; D001693:Biological Transport, Active / Q000187:drug effects; D002729:Chloromercuribenzoates / Q000494:pharmacology; D004140:Dinitrophenols / Q000494:pharmacology; D005459:Fluorides / Q000494:pharmacology; D005492:Folic Acid / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism; D007461:Iodoacetates / Q000494:pharmacology; D007536:Isomerism; D007700:Kinetics; D002955:Leucovorin / Q000494:pharmacology; D008727:Methotrexate / Q000378:metabolism / Q000494:pharmacology; D009154:Mutation; D010376:Pediococcus / Q000378:metabolism*; D013696:Temperature; D013763:Tetrahydrofolates / Q000378:metabolism*
D001386:Azides; D002729:Chloromercuribenzoates; D004140:Dinitrophenols; D007461:Iodoacetates; D013763:Tetrahydrofolates; D005492:Folic Acid; D005947:Glucose; D002955:Leucovorin; D005459:Fluorides; D008727:Methotrexate