title: The role of ferrichrome reductase in iron metabolism of Ustilago sphaerogena.
abstract: Ferrichrome, the ferric ionophore for Ustilago sphaerogena, can serve as a source of iron for the enzyme ferrochelatase (protoheme ferrolyase, EC 4.99.1.1) in this organism, but only after enzymatic removal of the iron from its carrier. U. sphaerogena contains a specific ferrichrome reductase (NADH:ferrichrome oxidoreductase) which catalyzes cellular dissociation of the complex by reduction of the metal to the ferrous state. A spectrophotometric assay was developed based on trapping of the ferrous ion produced by ferrozine. There is an apparent inhibition by oxygen which is thought to be due to re-oxidation of the metal under the assay conditions. The close structural analogue, ferrichrome A, is not a substrate, nor is the ester type siderochrome ferric hexahydro-N,N',N"-triacetylfusarinine C. Aluminum desferriferrichrome is inhibitory. The importance of this enzyme for the metabolism of iron in this organism is discussed.
mesh_terms: D001487:Basidiomycota / Q000201:enzymology*; D005291:Ferrichrome / Q000378:metabolism*; D005294:Ferrochelatase / Q000378:metabolism*; D006877:Hydroxamic Acids / Q000378:metabolism*; D007476:Ionophores; D007501:Iron / Q000378:metabolism; D008190:Lyases / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D010088:Oxidoreductases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014588:Ustilago / Q000201:enzymology*
chemical_list: D006877:Hydroxamic Acids; D007476:Ionophores; D009243:NAD; D005291:Ferrichrome; D007501:Iron; D010088:Oxidoreductases; C010421:ferrichrome reductase; D008190:Lyases; D005294:Ferrochelatase