Amino acid aminotransferase important for the metabolism of amino acids and Krebs-cycle related organic acids. No activity with D-Asp or D-Ala as amino donors. In plants, it is involved in nitrogen metabolism and in aspects of carbon and energy metabolism. 2-oxoglutarate + L-aspartate = L-glutamate + oxaloacetate Homodimer. accumulates in stromules, which are membrane-bound protrusions of the plastid envelope containing soluble stroma. Stromules are often found connecting plastids within a cell. Expressed in roots, cauline leaves, flowers, hypocotyl epidermis and root hair cells. Up-regulated in leaves during natural senescence. By ethylene and dark. In eukaryotes there are cytoplasmic, mitochondrial and chloroplastic isozymes. Belongs to the class-I pyridoxal-phosphate-dependent aminotransferase family.