<p>This entry represents FAD-dependent oxidoreductases. Characterised proteins within this family include glycerol-3-phosphate dehydrogenase (<db_xref db="EC" dbkey="1.1.99.5"/>), sarcosine oxidase beta subunit (<db_xref db="EC" dbkey="1.5.3.1"/>) and a number of deaminating amino acid oxidases (<db_xref db="EC" dbkey="1.4."/>). These genes have been consistently observed in a genomic context including genes for the import and catabolism of 2-aminoethylphosphonate (AEP). If the substrate of this oxidoreductase is AEP itself, then it is probably acting in the manner of a deaminating oxidase, resulting in the same product (phosphonoacetaldehyde) as the transaminase PhnW, but releasing ammonia instead of coupling to pyruvate:alanine. Alternatively, it is reasonable to suppose that the various ABC cassette transporters which are also associated with these loci allow the import of phosphonates closely related to AEP which may not be substrates for PhnW.</p>