label: 3-hydroxy-D-kynurenine + S-adenosyl-L-methionine => 3-hydroxy-4-methyl-D-kynurenine + S-adenosyl-L-homocysteine + H(+)
label_lc: 3-hydroxy-d-kynurenine + s-adenosyl-l-methionine => 3-hydroxy-4-methyl-d-kynurenine + s-adenosyl-l-homocysteine + h(+)