This enzyme is a member of the aromatic amino acid lyase family, other members of which are EC 126.96.36.199 (histidine ammonia-lyase), EC 188.8.131.52 (phenylalanine ammonia-lyase) and EC 184.108.40.206 (phenylalanine/tyrosine ammonia-lyase). The enzyme contains the cofactor 3,5-dihydro-5-methylidene-4H-imidazol-4-one (MIO), which is common to this family . This unique cofactor is formed autocatalytically by cyclization and dehydration of the three amino-acid residues alanine, serine and glycine . The enzyme is far more active with tyrosine than with phenylalanine as substrate, but the substrate specificity can be switched by mutation of a single amino acid (H89F) in the enzyme from the bacterium Rhodobacter sphaeroides [1,2].
EC 220.127.116.11 created 2008 (EC 18.104.22.168 created 1965, part-incorporated 2008)