Adrenal ferredoxin also known as adrenodoxin or adrenodoxin, mitochondrial or hepatoredoxin or ferredoxin-1 (FDX1) is a protein that in humans is encoded by the FDX1 gene. In addition to the expressed gene at this chromosomal locus (11q22), there are pseudogenes located on chromosomes 20 and 21.
Ferredoxin-1 is a small iron-sulfur protein that transfers electrons from NADPH through ferredoxin reductase to a terminal . This particular oxidation/reduction system is found in steroidogenic tissues, and is involved with the synthesis of bile acid and vitamin D. Ferredoxin-1 has been identified in a number of different tissues but all forms have been shown to be identical and are not tissue specific.