Amino acid oxidases:

The main route for the deamination of amino acids is transamination followed of glutamate through the oxidative deamination.  Moreover, a minor route also exists which includes direct oxidation of the amino acid through L-amino acid oxidase.  This enzyme utilizes FMN (flavin mononucleotide) as its coenzyme, with the resulting FMNH₂ being reoxidized through molecular O₂, a procedure which also produce the toxic H₂O₂. The H₂O₂ is rendered harmless through the action of catalase. Liver and Kidney are also rich in the FAD-containing D-amino acid oxidase.  Moreover, the function of this enzyme in animals is unclear, because the

Figure:  Action of L-amino acid oxidase.

 D-isomers of amino acids are rare in nature and only occurring in certain antiobiotics and. bacterial cell walls