- UbcH5A, a member of human E2 ubiquitin-conjugating enzymes, is closely related to SFT, a stimulator of iron transport, and is up-regulated in hereditary hemochromatosis. Gehrke, S.G., Riedel, H.D., Herrmann, T., Hadaschik, B., Bents, K., Veltkamp, C., Stremmel, W. Blood (2003)