ERG3

ERG3 or Sterol C-5 desaturase is a fungal enzyme originally from "Saccharomyces cerevisiae", the human ortholog of ERG3 is SC5D. ERG3 localizes to both the endoplasmic reticulum and vesicles, catalyzes the C5(6)-dehydrogenation of Episterol to 5-Dehydroepisterol, 5-Dehydroepisterol will be further converted into Ergosterol.