| Abstract: | Eggs at the early stages of embryogenesis and the larval fat body in Bombyx mori were confirmed to have an aldolase (ALD) isozyme type S. Its activity ratio with substrates fructose 1,6-bisphosphate (FBP) and fructose 1-phosphate (F1P) was 3. This isozyme was considered to be in favor of rather efficient utilization of F1P, since eggs in early stages of embryogenesis and the fat body had high activities of NADP-sorbitol dehydrogenase (NADP-SDH) and NAD-sorbitol dehydrogenase (NAD-SDH) responsible for the polyol pathway generating F1P. On the other hand, eggs at the second half of embryogenesis and the larval and adult muscle (plus epidermal cells and cuticle) possessed an ALD isozyme type F, whose FBP/F1P activity ratio was 10, suggesting that F1P utilization is less effective. This is in agreement with the fact that the NADP-SDH and NAD-SDH activities were low and the phosphofructokinase (PFK) activity was high in eggs at these stages and in muscle. Arch. Insect Biochem. Physiol. 36:139–148, 1997. © 1997 Wiley-Liss, Inc. |
