The physiological function of glutamate dehydrogenase (GDH) was investigated by treating germinating peanut (Arachis hypogaea L.) seeds with nucleoside triphosphate (NTP) solutions in order to alter the isoenzyme distribution patterns. The free nucleosides and nucleotides of the GTP-treated peanut were the highest [8.7 μmol g-1(f-m.)], and they decreased through the ATP-treated peanut [5.8 μmol g-1(f.m.)], and CTP-treated peanut [5.5 μmol g-1(f.m.)], to the UTP-treated peanut [4.1 μmol g-1(f.m.)]. The combination of 4 NTPs induced 20 % higher content of Pi [173 nmol g-1(f.m.)] than in the control, but the combined ATP+UTP treatment induced the lowest [93.0 nmol g -1(f.m.)] Pi. The 4 NTP treatment also induced the highest number of GDH isoenzymes (28) followed by the purine NTP treatments (15 to 20), but the pyrimidine NTP treatments and the combined purine + pyrimidine NTP treatments induced the lowest numbers (<15) of isoenzymes. The deamination/amination ratios were generally higher in the UTP (0.11), and CTP (0.06) treated peanuts than in the GTP (0.04), and ATP (0.07) treated peanuts. There were mutual relationships between higher numbers of GDH isoenzymes present in the GTP-, and ATP-treated peanuts and higher RNA (236.5 and 239.4 μg g-1, respectively) contents on one hand, and between the lower numbers of isoenzymes in the CTP-, and UTP-treated peanuts and lower RNA (162.0 and 152.5 μg g -1, respectively) contents. The recurrent relationships of the effects of the NTP treatments of peanut were UTP > ATP > CTP > GTP.
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