ABSTRACT
Amine oxidases (AO) have been found in a large number of tissues of practically all animal species. This chapter discusses the copper-dependent enzymes, though some flavin-adenin-nucleotide-dependent amine oxidases. Swine kidney diamine oxidase (SKDAO) is a Cu2+ -containing enzyme which oxidatively deaminates several diamines. SKDAO, like other enzymes of its class, shows a pinkish-yellow color due to its absorption maximum at 480 nm, which diminishes upon the addition of substrate under anaerobic conditions. Most Cu-AOs, including SKDAO, are functional as dimeric enzymes composed of two apparently identical subunits. SKDAO shows a noteworthy resistance towards heat denaturation. A carbonyl reagent-sensitive AO was partially purified from rabbit aorta. DAO activity was measured in homogenates of in vitro cultured human fibroblasts from normal and cystic fibrosis patients. Salivary glands contain a DAO that is able to rapidly oxidize putrescine, cadaverine, histamine, and, to a lesser degree, hexamethylene diamine and benzylamine.
