PURPOSE: A microorganism which contains a specific human lysozyme gene, is transformed with a recombined plasmid, which proliferates in the host cells and products human lysozyme, is cultured to produce human lysozyme.

CONSTITUTION: Human lysozyme gene which has, in the 5' terminal, the DNA segments coding the ribosome-binding site, another ribosome-binding site with a sequence that does not form hydrogen bonds at the start site of human lysozyme translation and the start site of human lysozyme translation, is expressed in the secondary structure of transcript mRNA. A microorganism producing human lysozyme, which has been transformed with recombinant plasmid that contains the gene, proliferates in the host cells and expresses human lysozyme is cultured in an appropriate medium to produce human lysozyme.