H2O + L-glutamate + NAD(+) = 2-oxoglutarate + H(+) + NADH + NH4(+) Inhibited by ethanol, acetone, acetonitrile and 2-propanol (65 to 70% inhibition) and to a lesser extent by methanol and dimethyl formamide (26 and 49 % inhibition respectively). No effect of glycerol or DMSO. kcat is 24 sec(-1) for glutamate in the presence of 3.2 M NaCl. kcat is 16 sec(-1) for NAD(+) in the presence of 3.2 M NaCl. kcat is 56 sec(-1) for 2-oxoglutarate in the presence of 3.2 M NaCl. kcat is 85 sec(-1) for NH(4)(+) in the presence of 3.2 M NaCl. kcat is 39 sec(-1) for NADH in the presence of 3.2 M NaCl. kcat is 17 sec(-1) for glutamate in the presence of 10% DMSO. kcat is 15 sec(-1) for NAD(+) in the presence of 10% DMSO. kcat is 46 sec(-1) for 2-oxoglutarate in the presence of 20% DMSO. kcat is 84 sec(-1) for NH(4)(+) in the presence of 20% DMSO. kcat is 47 sec(-1) for NADH in the presence of 20% DMSO. Optimum pH for oxidative deamination is 9.2. Optimum pH for reductive amination is 8.5. Optimum temperature is 70 degrees Celsius. The enzyme is entirely stable from 50 to 70 degrees Celsius and 55 % activity is retained after 30 min at 90 degrees Celsius. Homohexamer. The N-terminus is blocked. Strain NRC-36014 contains 4 distinct glutamate dehydrogenases while strain NRC-1 contains only 3. GdhX is only present in strain NRC-36014 (PubMed:15780999). Belongs to the Glu/Leu/Phe/Val dehydrogenases family. Was initially thought to be a NADP-specific glutamate dehydrogenase.