MTOX family consists of a group of FAD dependent oxidoreductases, including monomeric sarcosine oxidase (MSOX), pipecolate oxidase (PIPOX), heterotetrameric sarcosine oxidase (TSOX), D-amino acid oxidase (DAAO) and possibly two mitochondrial enzymes, sarcosine dehydrogenase (SDH) and dimethylglycine dehydrogenase (DMGDH) [, ].N-methyltryptophan oxidase (MTOX) catalyses the oxidative demethylation of N-methyl-L-tryptophan [], while Monomeric sarcosine oxidase (MSOX) catalyses the oxidative demethylation of sarcosine []. PIPOX is involved in the lysine degradation pathway where it oxidizes L-pipecolate, a neuromodulator of the GABA receptor complex []. Peroxisomal DAAO degrades D-serine, a modulator of neurotransmission in the brain. DMGDH and SDH are flavoproteins which catalyse the oxidative demethylation of dimethyl glycine to sarcosine and sarcosine to glycine, respectively [].
