Iron-reductases in the yeast Saccharomyces cerevisiae.
Several NAD(P)H-dependent ferri-reductase activities were detected in sub-cellular extracts of the yeast Saccharomyces cerevisiae. Some were induced in cells grown under iron-deficient conditions. At least two cytosolic iron-reducing enzymes having different substrate specificities could contribute to iron assimilation in vivo. One enzyme was purified to homogeneity: it is a flavoprotein (FAD) of 40 kDa that uses NADPH as electron donor and Fe(III)-EDTA as artificial electron acceptor. Isolated mitochondria reduced a variety of ferric chelates, probably via an 'external' NADH dehydrogenase, but not the siderophore ferrioxamine B. A plasma membrane-bound ferri-reductase system functioning with NADPH as electron donor and FMN as prosthetic group was purified 100-fold from isolated plasma membranes. This system may be involved in the reductive uptake of iron in vivo.
Lesuisse
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Laboratoire de Biochimie des Porphyrines, Universite Paris, France.
Crichton
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Labbe
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D002462:Cell Membrane / Q000201:enzymology; D003600:Cytosol / Q000201:enzymology; D005290:Ferric Compounds / Q000378:metabolism*; D008928:Mitochondria / Q000201:enzymology; D009243:NAD / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000302:isolation & purification / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology*
D005290:Ferric Compounds; D009243:NAD; D009249:NADP; D010088:Oxidoreductases; D009247:NADH, NADPH Oxidoreductases; C024253:ferrisiderophore reductase