Does an enzyme activity capable of phosphorylating sorbitol control utilization of sorbitol at the termination of diapause in eggs of the silkworm, Bombyx mori?

Abstract

1. 1. An enzyme activity capable of phosphorylating sorbitol was examined in the crude extracts from eggs of the silkworm, Bombyx mori. 2. 2. The optimum pH was approximately 9.5. The apparent K m values for ATP and sorbitol were about 0.12 and 2.3 mM, respectively. The full activity demanded 3 mM of Mg 2+. 3. 3. The activity remained at low and almost constant levels during the entire period of diapause. However, during post-diapause development, the activity increased from the stage of larval differentiation to the time of larval hatching. 4. 4. The above results suggested that the enzyme activity to phosphorylate sorbitol did not control the utilization of sorbitol at the termination of diapause. Further, its activity was discussed in relation to the maintenance of physiological levels of sorbitol-6-phosphate in hemolymph of larvae.