SRD5A2

3-oxo-5-alpha-steroid 4-dehydrogenase 2 is an enzyme that in humans is encoded by the SRD5A2 gene.

Steroid 5-alpha reductase catalyzes the conversion of the male sex hormone testosterone into the more potent androgen, dihydrotestosterone.

This gene encodes a microsomal protein expressed at high levels in androgen-sensitive tissues such as the prostate. The encoded protein is active at acidic pH and is sensitive to the 4-azasteroid inhibitor finasteride. Deficiencies in this gene can result in male pseudohermaphroditism, specifically pseudovaginal perineoscrotal hypospadias (PPSH).