A novel aspartokinase originating in a coryneform bacterium; a DNA encoding this enzyme; a recombinant DNA containing the above DNA; a coryneform bacterium having the above recombinant DNA or a coryneform bacterium having the DNA on its chromosome; and a process for producing L-lysine by culturing the above microorganism. Construction has been successfully made of a DNA encoding an aspartokinase with the relief of the synergistic feedback inhibition by L-lysine and L-threonine which originates in a corynebacterium and has a base sequence wherein the amino acid residue at the 311-position in the amino acid sequence represented by SEQ ID NO:18 is an amino acid other than Thr.
