Function
GLUD1 catalyses the oxidative deamination of Glu to 2-oxoglutarate and free NH4+ using either NAD+ or NADP+ as a co-factor. The reaction occurs with the transfer of a hydride ion from Glu's Cα to NAD(P)+, thereby forming 2-iminoglutarate, which is hydrolyzed to 2-oxoglutarate and NH4+. The reaction's equilibrium under standard circumstances greatly favors Glu formation over NH4+ (Go' ~ 30 kJ.mol-1) formation. For this reason, it was thought that the enzyme played an important role in ammonia detoxification, because since high are toxic, this equilibrium position would be physiologically important; it would help to maintain low . However, in individuals with a certain form of hyperammonemia resulting from a form of hyperinsulinism, the enzyme's activity is increased due to decreased GTP sensitivy, a negative regulator. These individual's blood ammonia levels are raised significantly, which would not be expected if the enzyme did indeed operate at equilibrium.
Read more about this topic: Glutamate Dehydrogenase 1
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