1975 Volume 78 Issue 6 Pages 1153-1160
1. The effects of lipoate and asparagusate on animal and plant enzymes of the TCA cycle and related metabolic pathways were studied.
2. Lipoate inhibited bovine liver glutamate dehydrogenase [EC 1. 4. 1. 3]. The inhibition may play a role in metabolic regulation.
3. Asparagusate inhibited lipoyl dehydrogenase [EC 1. 6. 4. 3] from asparagus and lettuce competitively with respect to lipoate. Asparagusate had practically no effects on other asparagus enzymes.
4. Asparagusate strongly inhibited lipoyl dehydrogenase, glutamate dehydrogenase, and isocitrate dehydrogenase [EC 1. 1. 1. 42] from animal sources, in competion with the corresponding substrate.
5. Asparagusate and lipoate also inhibited yeast glutamate dehydrogenase.
6. Based upon kinetic studies, the mode of these inhibitions is discussed.