Activity of NAD-sorbitol dehydrogenase is caused by biosynthesis of enzyme protein in diapause and non-diapause eggs of the silkworm, Bombyx mori

Abstract

1. 1. Using SDS-PAGE and immunoblotting analyses with anti-sorbitol dehydeogenase (EC 1.1.1.14, SDH) serum, changes in amount of SDH protein were examined in diapause and non-diapause eggs of the silkworm, Bombyx mori. 2. 2. When diapause eggs were exposed to 5°C from 2 days after oviposition to break the diapause gradually, SDH protein appeared after 50-day chilling, and then the amount increased along with chilling period. This changing pattern paralleled that in SDH activity. 3. 3. In diapause eggs treated with HCl after chilling at 5°C for 30 days to break the diapause quickly, and non-diapause eggs, changing patterns in amount of SDH protein also paralleled those in SDH activity. 4. 4. These results showed that SDH activity was caused by biosynthesis of SDH protein, independent of diapause or non-diapause eggs. 5. 5. Occurrence of SDH correlates with the three developmental phases: diapause termination, embryonic growth, and larval differentiation. In larva, SDH was mainly localized in the fat-body.