The role of amine oxidases in xenobiotic metabolism

Abstract

The amine oxidases of mammalian tissues are a heterogeneous family of enzymes that metabolise various monoamines, diamines and polyamines produced endogenously, or being absorbed as dietary or xenobiotic substances. The heterogeneous class of amine oxidases can be divided on an arbitrary basis of the chemical nature of their cofactors into two types. Monoamine oxidase (MAO) and an intracellular form of polyamine oxidase (PAO) contain flavin adenine dinucleotide (FAD) as their cofactor, whereas a second group of amine oxidases without FAD contain a cofactor possessing one or more carbonyl groups, making them sensitive to inhibition by carbonyl reagents such as semicarbazide; this group includes semicarbazide-sensitive amine oxidase (SSAO) and the connective tissue enzyme, lysyl oxidase. This article focuses on the general aspects of MAOs contribution to the metabolism of foreign toxic substances including toxins and illegal drugs. Another main objective of this review is to discuss the properties of PAO and SSAO and their involvement in the metabolism of xenobiotics.

Keywords::

• monoamine oxidases
• polyamine oxidases
• semicarbazide-sensitive amine oxidases
• xenobiotic metabolism

Acknowledgement

This work was supported by grants HL65416, ES-00676 and ES-013038 from the NIH. The authors thank Y Yang for assistance with NCBI GeneBank Data analysis.