Catalyzes the cleavage of L-kynurenine (L-Kyn) and L-3-hydroxykynurenine (L-3OHKyn) into anthranilic acid (AA) and 3-hydroxyanthranilic acid (3-OHAA), respectively. Has a preference for the L-3-hydroxy form. Also has cysteine-conjugate-beta-lyase activity. H2O + L-kynurenine = anthranilate + H(+) + L-alanine 3-hydroxy-L-kynurenine + H2O = 3-hydroxyanthranilate + H(+) + L-alanine Inhibited by o-methylbenzoylalanine (OMBA). Optimum pH is about 9.0 with L-kynurenine as substrate, and about 8.5 with DL-3-hydroxykynurenine as substrate. Amino-acid degradation; L-kynurenine degradation; L-alanine and anthranilate from L-kynurenine: step 1/1. Cofactor biosynthesis; NAD(+) biosynthesis; quinolinate from L-kynurenine: step 2/3. Homodimer. High levels in liver and kidney. Also detected in heart, retina, ovary. Lung, testis and brain. Inhibited by thiol reagents and heavy metal ions. Belongs to the kynureninase family.