Catalyzes the oxidative demethylation of sarcosine. Can also oxidize other secondary amino acids such as N-methyl-L-alanine. H2O + O2 + sarcosine = formaldehyde + glycine + H2O2 Binds 1 FAD per subunit. Pyrrole-2-carboxylate is a competitive inhibitor. N-(cyclopropyl)glycine (CPG) is a mechanism-based inhibitor and inactivates the enzyme by covalently modifying the flavin. Monomer. Belongs to the MSOX/MTOX family. MSOX subfamily.