L-Kynurenine + NADPH + Oxygen → L-3-Hydroxykynurenine + NADP + Water
N'-Formylkynurenine + Water → Formic acid + L-Kynurenine
L-Tryptophan + Oxygen → N'-Formylkynurenine
2-Amino-3-carboxymuconic acid semialdehyde
2-Amino-3-carboxymuconic acid semialdehyde → Quinolinic acid
3-Hydroxyanthranilic acid + Oxygen → 2-Amino-3-carboxymuconic acid semialdehyde
Hydroxykynurenine → 3-Hydroxyanthranilic acid