EHHADH is a bifunctional enzyme. It is one of the four enzymes of the peroxisomal beta-oxidation pathway. The N-terminal region of this protein contains enoyl-CoA hydratase activity while the C-terminal region contains 3-hydroxyacyl-CoA dehydrogenase activity. Defects in this gene are a cause of peroxisomal disorders such as Zellweger syndrome. EHHADH-null mice only exhibit a blunted peroxisome proliferative response when challenged with a peroxisome proliferator.