CCBL1 also known as Kynurenine--oxoglutrate transaminase1 isoform a. CCBL1 catalyzes the irreversible transamination of the L-tryptophan metabolite L-kynurenine to form kynurenic acid (KA) and it metabolizes the cysteine conjugates of certain halogenated alkenes and alkanes to form reactive metabolites. CCBL1 catalyzes the beta-elimination of S-conjugates and Se-conjugates of L-(seleno) cysteine, resulting in the cleavage of the C-S or C-Se bond. Recombinant human CCBL1 was expressed in E.coli and purified by using conventional chromatography techniques