title: Computer simulation of the urea cycle: trials for an appropriate model.
abstract: Several models of the urea cycle with normal and deficient enzymes were simulated on a desk-top computer in order to test if a model fitting data of patients suffering from deficiencies of urea cycle enzymes could be obtained. Discrepancies were notable if only the four enzymes of the urea cycle were used. The effect of adding either n-acetylglutamate synthetase and CPS or the mitochondrial transport system of ornithine and its catabolism to the model were tested singly or combined. The use of the combined model with the rate constants adjusted to recent data of the human enzymes together with a transport system for N-acetylglutamate out of the mitochondrium improved the results. Computer simulations are thus a useful tool for testing concepts of the functioning of the urea cycle.
mesh_terms: D000123:Acetyltransferases / Q000378:metabolism; D051046:Amino-Acid N-Acetyltransferase; D001119:Arginase / Q000378:metabolism; D001123:Argininosuccinate Lyase / Q000378:metabolism; D001124:Argininosuccinate Synthase / Q000378:metabolism; D003201:Computers; D006801:Humans; D008099:Liver / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000378:metabolism; D008954:Models, Biological; D009954:Ornithine Carbamoyltransferase / Q000378:metabolism; D014508:Urea / Q000378:metabolism*
chemical_list: D014508:Urea; D009954:Ornithine Carbamoyltransferase; D000123:Acetyltransferases; D051046:Amino-Acid N-Acetyltransferase; C494874:NAGS protein, human; D001119:Arginase; D001123:Argininosuccinate Lyase; D001124:Argininosuccinate Synthase