Mitochondrial glutamate dehydrogenase that catalyzes the conversion of L-glutamate into alpha-ketoglutarate. Plays a key role in glutamine anaplerosis by producing alpha-ketoglutarate, an important intermediate in the tricarboxylic acid cycle (PubMed:11032875, PubMed:16959573, PubMed:11254391, PubMed:16023112). Plays a role in insulin homeostasis (PubMed:9571255, PubMed:11297618). May be involved in learning and memory reactions by increasing the turnover of the excitatory neurotransmitter glutamate (By similarity). H2O + L-glutamate + NAD(+) = 2-oxoglutarate + H(+) + NADH + NH4(+) H2O + L-glutamate + NADP(+) = 2-oxoglutarate + H(+) + NADPH + NH4(+) Subject to allosteric regulation. Activated by ADP (PubMed:11903050). Inhibited by GTP and ATP (PubMed:11254391, PubMed:11032875, PubMed:9571255, PubMed:11903050, PubMed:11297618). ADP can occupy the NADH binding site and activate the enzyme (PubMed:16023112). Inhibited by SIRT4 (PubMed:16959573). Inhibited by HADH (By similarity). Homohexamer (By similarity). Interacts with HADH; this interaction inhibits the activation of GLUD1 (By similarity). Mostly translocates into the mitochondria, only a small amount of the protein localizes to the endoplasmic reticulum. ADP-ribosylated by SIRT4, leading to inactivate glutamate dehydrogenase activity (PubMed:16959573). Stoichiometry shows that ADP-ribosylation occurs in one subunit per catalytically active homohexamer (PubMed:16023112). The disease is caused by variants affecting the gene represented in this entry. Belongs to the Glu/Leu/Phe/Val dehydrogenases family. Glutamate dehydrogenase 1 entry