Ubiquitin-conjugating enzyme E2 D1(UBE2D1)belongs to the ubiquitin-conjugating enzyme family. Ubiquitination involves at least three classes of enzymes: ubiquitin-activating enzymes; or E1s; ubiquitin-conjugating enzymes; or E2s; and ubiquitin-protein ligases; or E3s. This enzyme is closely related to a stimulator of iron transport (SFT); and is up-regulated in hereditary hemochromatosis. It also functions in the ubiquitination of the tumor-suppressor protein p53 and the hypoxia-inducible transcription factor HIF1alpha by interacting with the E1 ubiquitin-activating enzyme and the E3 ubiquitin-protein ligases.