title: Aminotransferase-glutamate dehydrogenase-carbamyl phosphate synthase-I interactions.
abstract: Carbamyl phosphate synthase-I can enhance glutamate dehydrogenase-mitochondrial aspartate aminotransferase interactions. These results indicate that a complex can be formed between all three enzymes, which is stable in the presence of substrates and modifiers of these enzymes and consequently can convert NH4+ produced from aspartate into carbamyl phosphate. Citrate can remove both the aminotransferase and glutamate dehydrogenase from this complex, while malate primarily removes glutamate dehydrogenase. This suggests that these metabolites play a role in determining if these enzymes interact with carbamyl phosphate synthase-I or with enzymes of the Krebs cycle. Since the level of carbamyl phosphate synthase-I is quite high in liver mitochondria, these results suggest that this enzyme plays a major role in placing the aminotransferase and glutamate dehydrogenase in close proximity.
mesh_terms: D000818:Animals; D001219:Aspartate Aminotransferases / Q000378:metabolism*; D002222:Carbamoyl-Phosphate Synthase (Ammonia) / Q000378:metabolism*; D005969:Glutamate Dehydrogenase / Q000378:metabolism*; D007700:Kinetics; D008025:Ligases / Q000378:metabolism*; D008099:Liver / Q000201:enzymology; D008928:Mitochondria / Q000201:enzymology; D009391:Nephelometry and Turbidimetry / Q000379:methods; D051381:Rats
chemical_list: D005969:Glutamate Dehydrogenase; D001219:Aspartate Aminotransferases; D008025:Ligases; D002222:Carbamoyl-Phosphate Synthase (Ammonia)