The present invention relates to a novel aspartokinase derived from a Coryneform bacterium; a DNA encoding the 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 freed from concerted feedback inhibition by L-lysine and L-threonine derived from a Corynebacterium and has a nucleotide sequence encoding an amino acid sequence wherein the amino acid residue at position 311 is an amino acid other than Thr in the amino acid sequence shown by SEQ ID NO: 18.
