CCBL2 (KAT 3) catalyzes the reaction of kynurenine and pyruvate to form 4-(2-aminophenyl)-2,4-dioxobutanoate and alanine. CCBL2 is known only as the predicted protein product of a cloned human gene closely homologous to CCBL1 (Yu et al. 2006) and all of the structural and catalytic properties annotated here are inferred from those of CCBL1.