4-(2-amino-3-hydroxyphenyl)-2,4-dioxobutanoate + L-phenylalanine => 3-hydroxy-L-kynurenine + 3-phenylpyruvate
4-(2-amino-3-hydroxyphenyl)-2,4-dioxobutanoate + l-phenylalanine => 3-hydroxy-l-kynurenine + 3-phenylpyruvate