2026-04-13T00:53:01Zhttps://recercat.cat/oai/request

oai:recercat.cat:2445/531612025-12-05T14:53:28Zcom_2072_1057col_2072_478917col_2072_478924

00925njm 22002777a 4500 dc Arriarán, Sofía author Agnelli, Silvia author Fernández López, José Antonio author Remesar Betlloch, Xavier author Alemany, Marià, 1946- author 2014-04-01T13:27:58Z 2014-04-01T13:27:58Z 2012-10-06 2014-04-01T13:27:58Z A method for the measurement of carbamoyl-phosphate synthetase I activity in animal tissues has been developed using the livers of rats under normal and hyperproteic diets. The method is based on the incorporation of 14C-ammonium bicarbonate to carbamoyl-phosphate in the presence of ATP-Mg and N-acetyl-glutamate. The reaction is stopped by chilling, lowering the pH and adding ethanol. Excess bicarbonate is flushed out under a gentle stream of cold CO2. The only label remaining in the medium was that incorporated into carbamoyl-phosphate, since all 14C-CO2 from bicarbonate was eliminated. The method is rapid and requires only a low pressure supply of CO2 to remove the excess substrate. The reaction is linear up to 10 min using homogenate dilutions of 1:20 to 1:200 (w/v). Rat liver activity was in the range of 89±8 nkat/g. Hyperproteic diet resulted in a significant 1.4-fold increase. The design of the method allows for the processing of multiple samples at the same time, and incubation medium manipulation is unnecessary, since the plastic incubation vial and its contents are finally counted together. Dieta Enzims Urea Rates (Animals de laboratori) Diet Enzymes Urea Rats as laboratory animals A radiochemical method for carbamoyl-phosphate synthetase I: application to rats fed a hyperproteic diet