The enzyme from the bacterium Pantoea agglomerans produces D-beta-phenylalanine, an intermediate in the biosynthesis of the polyketide non-ribosomal antibiotic andrimid. The enzyme contains the cofactor 3,5-dihydro-5-methylidene-4H-imidazol-4-one (MIO), which is formed autocatalytically by cyclization and dehydration of the three amino-acid residues alanine, serine and glycine. cf. EC 5.4.3.10, phenylalanine aminomutase (L-beta-phenylalanine-forming).