Iron redox cycling in aerobic iron metabolism

Iron redox cycling in aerobic iron metabolism. A, iron uptake and efflux from the intestinal enterocyte. Fe(II) is the substrate for transport, whereas the substrate for input and output from this metabolic pathway is Fe(III). B, Fe(II) is both the input and output substrate from Ft redox cycling; Fe(III) is the metabolic intermediate in this pathway. C, iron uptake at the fungal PM inverts the Ft cycle in that Fe(III) is the input and output substrate with Fe(II) as the intermediate. D, iron cycling in the yeast vacuole (Vac) is a combination of Ft and fungal PM iron cycling. The Fe(II) is the input substrate, and Fe(III) is the output substrate with a Ft-like intravacuolar cycling between Fe(II) and Fe(III). All reductions are 1e−. Reductions associated with transmembrane iron trafficking involve NADPH-dependent reductases mediated by cytochrome heme centers; the reducing equivalents associated with Ft iron mobilization have not been characterized. All oxidations are catalyzed by a ferroxidase center and consume dioxygen. The question marks indicate that ionic iron speciation in the cytoplasm is largely uncharacterized.

Publication

Redox Cycling in Iron Uptake, Efflux, and Trafficking. (2010) Daniel J. Kosman. J Biol Chem. 2010 Aug 27;285(35):26729-26735. Figure: F2. All organisms Saccharomyces cerevisiae S288C Homo sapiens

Disease mentions