3-Hydroxykynurenine-13C2,15N (3-Hydroxy-DL-kynurenine-13C2,15N) hydrochloride is the 13C and 15N labeled 3-Hydroxykynurenine hydrochloride (HY-113294)[1]. 3-Hydroxykynurenine, a metabolite of tryptophan, is a potential endogenous neurotoxin whose increased levels have been described in several neurodegenerative disorders. 3-Hydroxykynurenine induces neuronal apoptosis[2].