ATP + L-aspartate = 4-phospho-L-aspartate + ADP Synthesis and activity are sensitive to the allosteric inhibitor lysine, one of the end metabolites of the aspartic acid family branched pathway. Amino-acid biosynthesis; L-lysine biosynthesis via DAP pathway; (S)-tetrahydrodipicolinate from L-aspartate: step 1/4. Homodimer. In the inactive form a homotetramer is formed. Aspartokinases I and II also catalyze the same reaction(s). Belongs to the aspartokinase family.