Studies with phorate,an organophosphate insecticide,on some enzymes of nitrogen metabolism inVigna mungo (L.) Hepper

Effects of phorate (Thimet-10 G) on the activities of enzymes of nitrogen metabolism,viz., glutamine synthetase (GS), glutamate dehydrogenase (GDH), and glutamate synthase (GOGAT) in the primary leaves, nitrogenase (N₂-ase) in detached root nodules, and protein concentration in the primary leaves ofVigna mungo (L.) Hepper have been studied. Phorate stimulated the activities of these enzymes and protein concentration in primary leaves at lower concentrations (50 to 200 mg per pot), but inhibited at higher concentrations (400 to 600 mg per pot). Although, the V_max for each enzyme with different treatments varied, the K_m value of each enzyme in the control and the treated plants remained unaltered.