Glutamate (Glu) dehydrogenase (GDH) catalyses the reversible amination of 2-oxoglutarate for the synthesis of Glu using ammonium as a substrate. This enzyme preferentially occurs in the mitochondria of companion cells of a number of plant species grown on nitrate as the sole nitrogen source. For a better understanding of the controversial role of GDH either in ammonium assimilation or in the su...

Two linked mutations affecting glutamate dehydrogenase (GDH) formation (gdh-1 and rev-2) had been isolated at a locus near the trp cluster in Klebsiella aerogenes. The properties of these two mutations were consistent with those of a locus containing either a regulatory gene or a structural gene. The gdhA gene from K. aerogenes was cloned and sequenced, and an insertion mutation was generated a...

The hyperinsulinism/hyperammonemia (HI/HA) syndrome is a form of congenital hyperinsulinism in which affected children have recurrent symptomatic hypoglycemia together with asymptomatic, persistent elevations of plasma ammonium levels. We have shown that the disorder is caused by dominant mutations of the mitochondrial enzyme, glutamate dehydrogenase (GDH), that impair sensitivity to the allost...

It has been reported that the hyperinsulinism-hyperammonemia syndrome is caused by mutations in glutamate dehydrogenase (GDH) gene that affects enzyme sensitivity to GTP-induced inhibition. To identify the GTP binding site(s) within human GDH, mutant GDHs at Tyr-266 or Lys-450 position were constructed by cassette mutagenesis. More than 90% of the initial activities were remained at the concent...

Glutamate dehydrogenase (GDH) is a hexameric enzyme that catalyzes the reversible conversion of glutamate to α-ketoglutarate and ammonia while reducing NAD(P)⁺ to NAD(P)H. It is found in all living organisms serving both catabolic and anabolic reactions. In mammalian tissues, oxidative deamination of glutamate via GDH generates α-ketoglutarate, which is metabolized by the Krebs cycle, leading t...

The aim of this work was to analyse the response of NH4 + assimilation in leaves of tobacco plants (Nicotiana tabacum L. cv. Tennessee 86), to different B applications (B1, 5 M H3BO3; B2, 10 M H3BO3; B3, 20 M H3BO3). The plants were grown under controlled environmental conditions and received a complete nutrient solution. In this experiment, we analysed the foliar concentrations of B and NH4 , ...

The present study was aimed to evaluate the therapeutic potential of Pimpinellatirupatiensis(Pt) by assaying the activities of selective mitochondrial enzymes in streptozotocin induced diabetic rats. Diabetic rats showed a significant (p < 0.01) reduction in the activities of oxidative enzymes Succinate dehydrogenase (SDH), Malate dehydrogenase (MDH), Glutamate dehydrogenase (GDH) and isocitrat...

The effect of cobalt on the lactic, pyuruvic acid contents and activity levels of aldolase, lactate dehydrogenase (LDH), succinate dehydrogenase (SDH) and isocitrate dehydrogenase (ICDH), glucose-6-phosphate dehydrogenase (G6-PDH) and glutamate dehydrogenase ( GDH) were studied. The decrease in the lactic acid content and increase in the pyruvic acid content in the silk gland of experimental si...

The hyperinsulinemia/hyperammonemia (HI/HA) syndrome—the secondmost common form of congenital hyperinsulinism—is a rare autosomal dominant disease manifested by hypoglycemic symptoms and elevated serum ammonia triggered by fasting or high-protein meals (1). In 1955, Cochrane et al. described a child and her father, both with hypoglycemia that was aggravated by consumption of a low-carbohydrate,...

Growth-promoting signaling molecules, including the mammalian target of rapamycin complex 1 (mTORC1), drive the metabolic reprogramming of cancer cells required to support their biosynthetic needs for rapid growth and proliferation. Glutamine is catabolyzed to α-ketoglutarate (αKG), a tricarboxylic acid (TCA) cycle intermediate, through two deamination reactions, the first requiring glutaminase...