Dopamine is oxidised to noradrenaline

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.

多巴胺β-羟化酶（DBH，多巴胺β-单加氧酶）是一种含铜的糖蛋白，由四个相同的亚基组成，催化多巴胺氧化生成去甲肾上腺素。该酶需以抗坏血酸作为电子供体。DBH定位于中枢神经系统中去甲肾上腺素能和肾上腺素能神经元。该酶存在于分泌囊泡中，以可溶性及膜结合两种形式存在。可溶性形式随儿茶酚胺通过胞吐作用分泌，而膜结合形式则被回收至囊泡中。