Amine oxidase activity of β-amyloid precursor protein modulates systemic and local catecholamine levels

Abstract

The catecholamines dopamine (DA), norepinephrine (NE) and epinephrine (E) are neurotransmitters and hormones that mediate stress responses in tissues and plasma. The expression of β-amyloid precursor protein (APP) is responsive to stress and is high in tissues rich in catecholamines. We recently reported that APP is a ferroxidase, subsuming, in neurons and other cells, the iron-export activity that ceruloplasmin mediates in glia. Here we report that, like ceruloplasmin, APP also oxidizes synthetic amines and catecholamines catalytically (K m NE=0.27 mM), through a site encompassing its ferroxidase motif and selectively inhibited by zinc. Accordingly, APP knockout mice have significantly high..