Metalloreductase STEAP3 is an enzyme that in humans is encoded by the STEAP3 gene.
STEAP3 is a metalloreductase, capable of converting iron from an insoluble ferric (Fe<sup>3+</sup>) to a soluble ferrous (Fe<sup>2+</sup>) form.
STEAP3 and other STEAP protein, with the exception of STEAP1, are predicted to contain a Di-nucleotide binding domain (Rossmann Fold). This has been shown using X-ray crystallography in the cases of STEAP3 and STEAP4 (PDB: 2VNS, 2VQ3 and 2YJZ).
STEAP3 has been shown to interact with BNIP3L and PKMYT1.