Binding of Reduced Cofactor to Glutamate Dehydrogenase

The binding of reduced cofactor (NADH) to glutamate dehydrogenase has been studied by gel filtration, equilibrium dialysis and fluorescence enhancement. The number of binding sites significantly exceeds 1 per polypeptide chain (1.3 per chain of molecular weight 56000), the saturation curve gives indications of slight positive interactions. The presence of GTP, glutamate and ADP, apart from increasing the affinity of NADH for glutamate dehydrogenase, appears to affect both the number of binding sites and the cooperativity of the binding.