SRD5A3
Steroid 5-alpha-reductase 3, also known as 3-oxo-5-alpha-steroid 4-dehydrogenase 3, is an enzyme that in humans is encoded by the SRD5A3 gene. It is one of three forms of 5α-reductase. Unlike SRD5A1 and SRD5A2, SRD5A3 has no apparent form in androgen processing or signaling. Instead, SRD5A3 reduces polyprenol to dolichol, which is necessary for N-linked glycosylation of proteins and some lipids.