Isolation and characterization of malic enzyme from the pupa of Bombyx mori

Malic enzyme, which requires NADP+ as a coenzyme, was isolated and purified from pupae of the silkworm, Bombyx mori. The purified enzyme appeared homogeneous and had a molecular weight of 195,000 on polyacrylamide gel electrophoresis. The optimum pH for the oxidative decarboxylation of malate, measured in terms of the increase of NADPH (MH activity) and CO2 (MC activity), was pH 7.5, while that for the decarboxylation of oxaloacetate measured in terms of the increase of CO2 (OC activity) was pH 4.6. Several differences between MH and OC activity were investigated.