Dopamine beta-hydroxylase (DBH; dopamine beta-monooxygenase) is a copper-containing glycoprotein consisting of four identical subunits and catalyzes the oxidation of dopamine to norepinephrine. It requires ascorbic acid as an electron donor. DBH is localized in the norepinephrinergic and epinephrinergic neurons in the central nervous system. The enzyme exists in the secretory vesicles as both soluble and membrane-bound forms. The soluble form is secreted with catecholamines by exocytosis whereas the membrane-bound form is recycled into the vesicles.
Acyl-CoA dehydrogenase family member 11 (ACAD11) is a mitochondrial membrane-bound enzyme that can catalyse the alpha, beta-dehydrogenation of acyl-CoA esters. ACAD11 shows highest expression in the brain and is shown to dehydrogenate the C22 acyl-CoA behenoyl-CoA (BH-CoA) to 2,3-dehydrobehenoyl-CoA (DBH-CoA) (He et al. 2011).