ABSTRACT
Compounds that inhibit amine oxidases (AO) can often be classified into alternative types such as substrate analogs, time-dependent enzyme inactivators, copper-chelating reagents, substrate inhibitors, product inhibitors, or suicide substrates. The copper AO are inhibited by a number of substances that have not always been clearly fitted into any of the previous schemes. The presence of copper in AO has been established by both chemical and spectroscopic analysis and strong confirmation of the necessity of copper for enzyme activity came from the fact that incubation with Diethyldithiocarbamate gave precipitation of the copper chelate complex and loss of enzyme activity. Incubation of polyamines with plasma AO leads to the formation of cytotoxic aminoaldehydes and acrolein and attempts are often made to block these using AO inhibitors. Comparative studies of plant and mammalian AO using substrate analogs, imidazoles, carnosine, and anserine have led to the conclusion that the mammalian enzymes are more adapted to histamine oxidation and the plant enzymes for diamine oxidation.
