Center for Bioinformatics
Oxidoreductases | Transferases | Hydrolases | Lyases | Isomerases | Ligases

Basic Information

Enzyme Number

Official Name

carbamoyl-phosphate synthase (ammonia)

Name from literature

Carbamyl phosphate synthetase I

Pathway from literature

free ammonia into the urea cycle

Pathway from KEGG

Amino Acid Metabolism; Urea cycle and metabolism of amino groups; map00220

Amino Acid Metabolism; Glutamate metabolism; map00251

Amino Acid Metabolism; Arginine and proline metabolism; map00330

Energy Metabolism; Nitrogen metabolism; map00910


Human (9606)

Genome localization

2q35[1373 ],

Rate-limiting Description

"CPS1 is a rate-limiting enzyme in urea cycle and is located in mitochondria." (18026163)

"Carbamyl phosphate synthetase I (CPSI) determines the rate-limiting entry of free ammonia into the urea cycle." (15050969)

Regulatory Information

Upstream transcription factor


Regulatory type






transcriptional factor;glucocorticoid receptor(2908)

"In vivo footprinting assays showed that the accessory transcription factors of the glucocorticoid response unit bound to their response elements in carbamoylphosphate synthetase-I-positive cells, irrespective of whether carbamoylphosphate synthetase-I expression was induced with hormones. In contrast, the binding of glucocorticoid receptor to the carbamoylphosphate synthetase-I glucocorticoid response unit was dependent on treatment of the cells with glucocorticoids. " (17140418)

Gene ontology

Gene ontology

GO:0006541 (P) glutamine metabolic process [P31327 ];
GO:0005739 (C) mitochondrion [P31327 ];
GO:0000050 (P) urea cycle [P31327 ];
GO:0004087 (F) carbamoyl-phosphate synthase (ammonia) acti... [P31327 ];
GO:0005515 (F) protein binding [P31327 ];
GO:0005524 (F) ATP binding [P31327 ];

Tissue expression

Tissue From HPRD

Intestine [01995 ];
Liver [01995 ];

Tissue specificity

Primarily in the liver and small intestine [P31327 ];

Subcellular localization


mitochondrion [P31327 ];

Disease relevance


Defects in CPS1 are associated with susceptibility to familial persistent pulmonary hypertension of the newborn [MIM:265380];
also called congenital alveolar capillary dysplasia or CACD. Failure of the transition to a cardiorespiratory circulation at birth results in persistent pulmonary hypertension of the newborn. Characterized by elevated pulmonary vascular resistance with extrapulmonary right-to-left shunting of blood across the patent ductus arteriosus or the foramen ovale, persistent pulmonary hypertension can cause life-threatening hypoxemia in newborn infants. Transitional pulmonary hypertension occurs in 1.9 of every 1000 newborn infants and is associated with a mortality rate of 11 percent [P31327 ];

Defects in CPS1 are the cause of carbamoyl phosphate synthetase 1 deficiency (CPS1D) [MIM:237300]. CPS1D is an autosomal recessive disorder of the urea cycle causing hyperammonemia. Clinical features include protein intolerance, intermittent ataxia, seizures, lethargy, developmental delay and mental retardation [P31327 ];




Entrez Gene




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  Last Modified: 2009-03-24  
  Design by Zhao Min