Introduction

The history of investigations on amine oxidases (AO) represents a striking interplay of several different disciplines, each using different techniques and approaches. There have been a number of reviews of the early history of the AO. The first in vitro study was the demonstration in 1928 of the presence of tyramine oxidase in liver preparations by Mary Hare. Blaschko and colleagues showed that the pharmacologically active catecholamines were substrates of the same monoamine oxidase preparation. From the biochemical point of view, one of the most interesting aspects of the AOs is the nature of the cofactors present and the mechanism of their action. Most AOs have flavin or metal cofactors. A number of AOs do not contain flavin cofactors, but do contain stoichiometric amounts of copper, which are needed for activity. Included in this group are AOs from Aspergillus niger, pea seedlings, bovine and pig plasma, and pig kidney.