title: Negative cooperativity in human liver argininosuccinase.
abstract: The kinetic properties of argininosuccinase (L-argininosuccinate arginine-lyase, EC 4.3.2.1.) were investigated. Negative cooperativity was observed in the response of the enzyme to the substrate argininosuccinate and GTP behaved as a positive allosteric effector. These effects were observed in 60 mM potassium phosphate but not in 50 mM Tris-HCl. Structural changes in the protein molecule are suggested to explain previous observations of Michaelis-Menten kinetics for this enzyme.
mesh_terms: D000494:Allosteric Regulation / Q000187:drug effects; D001123:Argininosuccinate Lyase / Q000378:metabolism*; D001125:Argininosuccinic Acid / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008190:Lyases / Q000378:metabolism*; D011487:Protein Conformation
chemical_list: D001125:Argininosuccinic Acid; D006160:Guanosine Triphosphate; D008190:Lyases; D001123:Argininosuccinate Lyase