Reductive and non-reductive mechanisms of iron assimilation by the yeast Saccharomyces cerevisiae.
Iron reduction and uptake was studied in wild-type and haem-deficient strains of Saccharomyces cerevisiae. Haem-deficient strains lacked inducible ferri-reductase activity and were unable to take up iron from different ferric chelates such as Fe(III)-citrate or rhodoturulic acid. In contrast, ferrioxamine B was taken up actively by the mutants as well as by the wild-type strains. At a low extracellular concentration, uptake was insensitive to ferrozine and competitively inhibited by Ga(III)-desferrioxamine B. Extracellular reductive dissociation of the siderophore occurred at higher extracellular concentrations. Two mechanisms appear to contribute to the uptake of ferrioxamine B by S. cerevisiae: one with high affinity, by which the siderophore is internalized as such and another with lower affinity by which iron is dissociated from the ligand prior to uptake.
Lesuisse
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Laboratoire de Biochimie des Porphyrines, Institut Jacques Monod, Université Paris, France.
Labbe
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D000622:Aminolevulinic Acid / Q000494:pharmacology; D003470:Culture Media; D003676:Deferoxamine / Q000378:metabolism / Q000494:pharmacology; D038181:FMN Reductase; D005290:Ferric Compounds / Q000378:metabolism*; D006418:Heme / Q000502:physiology; D007501:Iron / Q000494:pharmacology; D007502:Iron Chelating Agents / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D010084:Oxidation-Reduction; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*
D003470:Culture Media; D005290:Ferric Compounds; D007502:Iron Chelating Agents; D006418:Heme; C002577:ferrioxamine B; C025314:ferric citrate; D000622:Aminolevulinic Acid; D007501:Iron; D038181:FMN Reductase; D009247:NADH, NADPH Oxidoreductases; C023903:ferric citrate iron reductase; D003676:Deferoxamine