Characteristics of malic enzyme from the cysticerci of Taenia crassiceps (Zeder, 1800).

Kinetic parameters of partly purified malic enzymes (NADP+: L-malate oxidoreductase (decarboxylating) EC 1.1.1.40) from the cytoplasm and mitochondria of Taenia crassiceps cysticerci were compared. The cytoplasmic malic enzyme differed from the mitochondrial malic enzyme in the K'M for malate; other studied properties were identical. The chromatographies of both the cytoplasmic and mitochondrial enzymes were identical. They exhibited a hyperbolic dependence of the activity on malate concentration, sigmoidal kinetics was not observed. The effects of succinate and fumarate known as positive modulators of the activity of malic enzymes from other sources were not observed either in cytoplasmic or mitochondrial enzymes from T. crassiceps. It was found that the two enzymes can be partly inhibited by ATP. Molecular weight of the malic enzyme from T. crassiceps cysticerci was determined by chromatography on Sephadex G-200 (Mw = 116,700) and a four-step purification of the enzyme was performed. The properties of malic enzymes from the cytoplasm and mitochondria of T. crassiceps are compared with those of the malic enzymes from other parasitic worms and higher organisms.