Iron uptake from ferrichrome A and iron citrate in Ustilago sphaerogena.

摘要: Double radioactive label transport assays with iron, chromium, and gallium chelates were used to investigate the mechanism of iron uptake by Ustilago sphaerogena. In iron-deficient cells, ferrichrome A was taken up without appreciable ligand. Iron-sufficient cells partially accumulated ligand metal. The chromium- gallium-containing analogs transported as intact chelates. Ferrichrome inhibited dipyridyl. data suggest that chelate binds a specific receptor, is then separated from at membrane reduction, metal released inside cell while exterior. reduction step not rate limiting. Iron chelated citrate an energy-dependent process. Uptake sensitive dipyridyl ferrozine. Chromic ion transported, suggesting rather than chelate, recognized receptor or required for transport.