title: Efflux system for pyridoxine in Schizosaccharomyces pombe.
abstract: Pyridoxine-charged Schizosaccharomyces pombe released pyridoxine rapidly at 30 degrees C: very low amounts of three other B6 vitamers were also released. The rate of efflux was temperature-dependent. The initial rate of efflux was dependent on the concentration of pyridoxine in the cells: the rate was almost zero at lower than 0.02 mM and became saturated at higher than 0.2 mM. Na+, sodium azide, and dinitrophenol increased the rate in both the presence and absence of D-glucose. Mg++, thiamine, and menadione inhibited the efflux. The intracellular concentration of ATP did not significantly affect the efflux rate. The system may be dependent on a membrane potential of the yeast cells. It was found that the fission yeast cells have a gate or carrier system for efflux of pyridoxine, which was distinct from that in Saccharomyces cerevisiae.
authors.affiliation: Department of Bioresources Science, Faculty of Agriculture, Kochi University, Nankoku Kochi, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Hirose
authors.forename: R
authors.initials: R
authors.lastname: Chumnantana
authors.forename: T
authors.initials: T
authors.lastname: Nakashima
authors.forename: M
authors.initials: M
authors.lastname: Ashiuchi
authors.forename: T
authors.initials: T
authors.lastname: Yagi
mesh_terms: D019297:2,4-Dinitrophenol / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000378:metabolism; D001692:Biological Transport; D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology; D011736:Pyridoxine / Q000378:metabolism* / Q000494:pharmacology; D012568:Schizosaccharomyces / Q000187:drug effects / Q000378:metabolism*; D019810:Sodium Azide / Q000494:pharmacology; D013696:Temperature; D013831:Thiamine / Q000494:pharmacology; D014475:Uncoupling Agents / Q000494:pharmacology; D014812:Vitamin K / Q000494:pharmacology; D014815:Vitamins / Q000494:pharmacology
chemical_list: D002241:Carbohydrates; D004791:Enzyme Inhibitors; D014475:Uncoupling Agents; D014815:Vitamins; D014812:Vitamin K; D010042:Ouabain; D000255:Adenosine Triphosphate; D019810:Sodium Azide; D008274:Magnesium; D005947:Glucose; D011736:Pyridoxine; D019297:2,4-Dinitrophenol; D013831:Thiamine