Catalyzes the irreversible transamination of the L-tryptophan metabolite L-kynurenine to form kynurenic acid (KA). As a member of the malate-aspartate shuttle, it has a key role in the intracellular NAD(H) redox balance. Is important for metabolite exchange between mitochondria and cytosol, and for amino acid metabolism. Facilitates cellular uptake of long-chain free fatty acids (By similarity). 2-oxoglutarate + L-aspartate = L-glutamate + oxaloacetate 2-oxoglutarate + L-kynurenine = H2O + kynurenate + L-glutamate Homodimer. Located in the mitochondria of liver, pancreas, spleen, heart, pituitary gland and submandibular gland cells. In kidney, located in the mitochondria, on the cell surface of regions with protrusions in distal tubules, on the apical cell surface of protrusions along the microvilli in cortical collecting ducts, in condensing vacuoles, on the cell surface at cell boundaries of adjoining kidney cells and on the cell surface of endothelial cells lining capillaries in the glomerulus. Also located at the cell surface of endothelial cells lining arterioles and on the cell surface of lymphocytes. Expressed in all tissues tested: liver, pancreas, kidney, heart, spleen, arterioles, and lymphocytes. In eukaryotes there are cytoplasmic, mitochondrial and chloroplastic isozymes. Belongs to the class-I pyridoxal-phosphate-dependent aminotransferase family.