title: Activation of carbamoyl phosphate synthase by N-acetyl-L-aspartate.
abstract: Carbamoyl phosphate synthase from liver of both rat and frog, normally dependent on N-acetyl-l-glutamate (on the basis of K(m) and physiological concentrations) as an activator, was shown to be activated by high concentrations of N-acetyl-l-aspartate. However, the high concentrations of N-acetyl-l-aspartate required for activation produce non-competitive inhibition. Similarly, high concentrations of N-acetyl-l-glutamate, in very large excess of the amount required to activate the enzyme, inhibit. The limit for N-acetyl-l-glutamate as an impurity in N-acetyl-l-aspartate was found to be less than 1 in 5000 parts, far below the 1 in 250 parts needed to produce the activation observed with N-acetyl-l-aspartate.
mesh_terms: D000818:Animals; D001001:Anura; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D001665:Binding Sites; D004789:Enzyme Activation; D008099:Liver / Q000201:enzymology; D008722:Methods; D010770:Phosphotransferases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats
chemical_list: D001224:Aspartic Acid; D010770:Phosphotransferases