THE PROPERTIES OF MONOCLONAL-ANTIBODY AGAINST SEPIAPTERIN REDUCTASE FROM FAT-BODY OF THE SILKWORM, BOMBYX-MORI

A specific monoclonal antibody prepared for the 29-kDa subunit of silkworm fat body sepiapterin reductase (SPR) was able to recognize the subunit in crude extract of fat body after SDS treatment. Although SPR from the silkworm fat body has biochemical properties similar to those reported for SPR from mammalian sources, especially rat erythrocytes, the antibody failed to recognize the 28-kDa subunit of rat erythrocyte SPR. This result indicates that SPR from silkworm fat body has a different amino-acid sequence from that of the rat erythrocyte enzyme. Sepiapterin reductase activity has not been found in crude extract of fat body from the silkworm mutant lemon. Although the antibody recognized only 29-kDa protein in the crude extract of silkworm fat body from normal strain after SDS-treatment, the antibody recognized only an approximately 80-kDa protein in the crude extract of the lemon mutant after SDS-treatment.