It is an object of the present invention to provide isozymes of the lachrymatory factor producing enzyme, the amino acid sequences of these isozymes and a gene that codes for these amino acid sequences, and the present invention relates to three types of isozymes of the lachrymatory factor producing enzyme that contributes to the production of the lachrymatory factor that is present in onions and the like, amino acid sequences indicated by SEQ ID Nos. 1 to 3 which constitute the proteins or polypeptides of these isozymes, DNA indicated by SEQ ID Nos. 4 and 5 which contains base sequences that code for the abovementioned proteins or polypeptides, a method of producing the abovementioned isozymes, a recombinant vector which contains the abovementioned DNA, a transformant formed by transforming a host cell with the abovementioned recombinant vector, a method of producing proteins or polypeptides that have lachrymatory factor producing enzyme activity by culturing the abovementioned host cell, and anti-sense RNA which has a base sequence that is complementary to that of the mRNA corresponding to the abovementioned DNA.
