Dopamine-β-Hydroxylase: A Tetrameric Glycoprotein

Abstract Dopamine-β-hydroxylase (EC 1.14.2.1) has been isolated as a pure protein from bovine-adrenal glands. Although the molecular weight of the native protein is well established (290,000), sodium dodecyl sulfate-gel electrophoresis under dissociating conditions gave a single band with a molecular weight of about 75,000. The enzyme contains about 4% carbohydrate, which consists of residues of mannose, glucosamine, galactose, glucose, fucose, and sialic acid. The pure enzyme also contains about 4 atoms of copper per molecule. It is concluded that dopamine-β-hydroxylase is a tetrameric glycoprotein.