| carbamoyl phosphate | H2NCO-OPO32-;a reactive intermediate capable of transferring its carbamoyl group (H2NCO-) to an acceptor molecule, forming citrulline from ornithine in the urea cycle, and ureidosuccinic acid from aspartic acid in pyrimidine ring formation. (05 Mar 2000) |
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| carbamoyl phosphate synthetase | A phosphotransferase catalyzing the formation of carbamoyl phosphate. There are two significant isozymes. Carbomoyl phosphate synthetase I is a mitochondrial enzyme that catalyses the reaction of 2ATP, NH3, CO2, and H2O to carbamoyl phosphate, 2ADP, and Pi. It is activated by N-acetylglutamate and participates in urea biosynthesis. A deficiency of carbamoyl phosphate synthetase I can result in hyperammonaemia. Carbamoyl phosphate synthetase II is a cytosolic enzyme that, under physiological conditions, uses l-glutamine as the nitrogen source (producing l-glutamate) instead of NH3, is not activated by N-acetylglutamate, and is found in pyrimidine biosynthesis. (05 Mar 2000) |
| carbamoyl-phosphate synthase (ammonia) | <enzyme> An enzyme that catalyses the formation of carbamoyl phosphate from ATP, carbon dioxide, and ammonia. This enzyme is specific for arginine biosynthesis or the urea cycle. Chemical name: Carbon dioxide:ammonia ligase (ADP-forming, carbamate-phosphorylating) Registry number: EC 6.3.4.16 (12 Dec 1998) |
| carbamoyl-phosphate synthase (glutamine-hydrolyzing) | <enzyme> An enzyme that catalyses the formation of carbamoyl phosphate from ATP, carbon dioxide, and glutamine. This enzyme is important in the de novo biosynthesis of pyrimidines. Chemical name: Carbon dioxide:L-glutamine amido-ligase (ADP-forming, carbamate-phosphorylating) Registry number: EC 6.3.5.5 (12 Dec 1998) |
| carbamoylaspartate dehydrase | dihydro-orotase |
| carbamoylation | Transfer of the carbamoyl from a carbamoyl-containing molecule (e.g., carbamoyl phosphate) to an acceptor moiety such as an amino group. (05 Mar 2000) |
| carbamoylcarbamic acid | NH2CONHCOOH; urea carbonic acid;its amide is biuret (allophanamide). Synonym: carbamoylcarbamic acid, N-carboxyurea. (05 Mar 2000) |
| carbamoylphosphate synthetase deficiency | <biochemistry> Carbamoylphosphate synthetase is the initial enzyme of the urea cycle, catalysing the synthesis of carbamoylphosphate from ammonia, bicarbonate and ATP as the first step of ammonia detoxification. The enzyme is an intramitochondrial form called CPS I. A different isozyme found in the cytoplasm, called CPS II, is much less active and apparently not involved in the urea cycle. The deficiency state is autosomal recessive and presents in infancy with massive hyperammonaemia and neurologic deficits in survivors. Diagnosis is suggested by the blood biochemistry and confirmed by specific enzyme assay on liver or rectal biopsy. Prenatal diagnosis by molecular methods has been used successfully in informative families. Inheritance: autosomal recessive. (07 Apr 1998) |
| carbamoyltransferase | Enzymes transferring carbamoyl groups from one compound to another (e.g., aspartate carbamoyltransferase, ornithine carbamoyltransferase). Synonym: transcarbamoylase. (05 Mar 2000) |
| carbamoylurea | <chemistry> A white, crystalline, nitrogenous substance, C2O2N3H5, formed by heating urea. It is intermediate between urea and cyanuric acid. Origin: Pref. Bi- + urea. Source: Websters Dictionary (01 Mar 1998) |
| carbamyl | Former spelling of carbamoyl. (05 Mar 2000) |
| carbamyl phosphate | <chemical> Phosphate salt of carbamic acid. Chemical name: Carbamic acid, monoanhydride with phosphoric acid (12 Dec 1998) |
| carbamylation | Former spelling of carbamoylation. (05 Mar 2000) |
| carbamylcholine chloride | A cholinomimetic drug which reacts with and activates both muscarinic and nicotinic receptors. It is slowly hydrolyzed and thus its effects far outlast those of acetylcholine. Used medically to stimulate smooth muscle, as in paralytic ileus following surgery. (05 Mar 2000) |
| carbanion | <chemistry> A negatively charged carbon atom. (07 Apr 1998) |