Bifunctional enzyme that has both L-aspartate decarboxylase and transaminase activity. Has high activity with L-aspartate, and much lower activity with D-aspartate, L-lysine and L-glutamine. H(+) + L-aspartate = CO2 + L-alanine 2-oxoglutarate + L-aspartate = L-glutamate + oxaloacetate Inhibited by 10 mM Co(2+), Mn(2+) and Ni(2+), and by 1 mM Cu(2+) and Hg(2+). Optimum pH is 5. Optimum temperature is 45 degrees Celsius. Homododecamer. Belongs to the class-I pyridoxal-phosphate-dependent aminotransferase family.