The enzyme 5ñ-hydroxysteroid dehydratase () catalyzes the chemical reaction
This enzyme belongs to the family of lyases, specifically the hydro-lyases, which cleave carbon-oxygen bonds. The systematic name of this enzyme class is 5ñ-ergosta-7,22-diene-3ò,5-diol 5,6-hydro-lyase (ergosterol-forming). This enzyme is also called 5ñ-ergosta-7,22-diene-3ò,5-diol 5,6-hydro-lyase.