Plays a key role in early steps of protein N-linked glycosylation by being required for the conversion of polyprenol into dolichol . Dolichols are required for the synthesis of dolichol-linked monosaccharides and the oligosaccharide precursor used for N-glycosylation . Acts as a polyprenol reductase that promotes the reduction of the alpha-isoprene unit of polyprenols into dolichols in a NADP-dependent mechanism . Also able to convert testosterone (T) into 5-alpha-dihydrotestosterone (DHT) (, ).
Subcellular locations: Endoplasmic reticulum membrane
Expressed in preadipocytes (at protein level) . Overexpressed in hormone-refractory prostate cancers (HRPC). Almost no or little expression in normal adult organs.