NADP +-specific Isocitrate Dehydrogenase from Bombyx mori, Order of Substrate Addition and Product Release

The kinetics of the reaction of NADP+-specific isocitrate dehydrogenase was examined by using the enzyme purified from the pupae of silkworm, Bombyx mori. The binding of the individual substrates, isocitrate and NADP⁺, depended upon each other, and was competitive with the reaction products, CO,, α-ketoglutarate and NADPH. The mechanism appears to be of a rapid equilibrium random type. These findings were very similar to those reported for NADP+-specific isocitrate dehydrogenases isolated from several sources

Developmental Changes in the Activities of Several Enzymes and in Metabolites of Bombyx mori

In order to elucidate metabolic regulation with regard to carbohydrates during metamorphosis of Bombyx mori, two key enzymes related to gluconeogenesis and glycolysis were measured for their levels of activity during the period of pupal-adult development, by use of crude extract from the whole bodies of the insect. Moreover, the changes in concentration of glucose-6-phosphate and citrate were also examined. The resulting patterns of fructose-l, 6-diphosphatase and phosphofructokinase were characterized by their apparent high activity levels at the middle of pupal age and before emergence, respectively. Based on the observed patterns in concentration of glucose-6-phosphate and citrate, the roles and oscillatory changes of both metabolites are briefly discussed

Developmental ‘Changes in Activities of Several Enzymes Involved in Glycolysis and TCA Cycle during the Pupal Period of Bombyx mori

In order to elucidate metabolic regulation with regard to carbohydrates and lipids during metamorphosis of Bombyx mori, eight enzymes related to glycolysis and TCA cycle were measured for their levels of activity during the period from the day of pupal ecdysis to 2 days after adult emergence, by use of crude extract from the whole bodies of the insect. The resulting patterns could be grossly divided into two groups. Glucose-B-phosphate dehydrogenase, NADP-specific isocitrate dehydrogenase, malic enzyme, hexokinase and pyruvate kinase were characterized by their apparent high activity levels during larval-pupal development followed by low levels at emergence. On the contrary, aconitase, NAD-specific isocitrate dehydrogenase and malate dehydrogenase were characterized by their apparent low levels during pupal period and by an abrupt increase in activity before emergence. The roles of these enzymes in metamorphosis are briefly discussed

Structure of the newly found green turtle egg-white ribonuclease

The structure of GTRNase has been solved at 1.60 Å resolution by the molecular-replacement technique