Carbamoyl phosphate synthetase I (CPS I)
Cofactors used
Clinical / pharmacological. CPS I deficiency: hyperammonaemia, normal orotic acid
What it does, reaction by reaction
Urea Cycle Amino Acid & Nitrogen Metabolism · Mitochondrial matrix + cytosol
NH₄⁺ + HCO₃⁻ + 2 ATP → carbamoyl phosphate + 2 ADP + Pᵢ
Converts NH4+ HCO3- ATP into Carbamoyl phosphate ADP Pi
› Notes
In the mitochondrial matrix, carbamoyl phosphate synthetase I (CPS I) uses MgATP and requires N-acetylglutamate (NAG) as an obligatory allosteric activator. This is the rate-limiting, committed, and essentially irreversible step of the urea cycle; it consumes two high-energy phosphate bonds.
Showing all 1 reactions.
What accelerates and inhibits it
Regulation is pathway-specific, so each context is listed separately
Urea Cycle
N-acetylglutamate (obligatory); increased mitochondrial ammonia
Absence of N-acetylglutamate; no principal direct physiologic inhibitor
Glucagon and cortisol increase expression during fasting/high-protein catabolism; insulin lowers net ureagenic demand in the fed state
Recent literature
Europe PMC · fetched just now · sorted by publication date
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1
Genetic overlap between estimated glomerular filtration rate and cardiovascular disease identifies potential targets for cardiorenal syndrome.
Li W, Chen Y, Xiong W, Yuan S. · 2026-08-27
open access unreviewed -
2
Neurotransmitter receptor-associated gene signature: prognostic and immunosuppressive microenvironment in NSCLC.
Yang Y, Ge A, Xu Y, Li J, Shi W, Wang J, Zhao Z. · 2026-01-06
open access unreviewed -
3
Essential Oral Single Nutritional Therapy Products for Inherited Metabolic Diseases: Evidence and Consensus Assessment Using a Modified Delphi Method.
Stolwijk NN, Penninx BMF, Bosch AM, Langeveld M, Salomons GS, Hollak CEM, Essential Nutritional Therapy Produ… · 2026-11-01
open access unreviewed -
4
Inborn Errors of Metabolism: Pathophysiological Insights, Diagnostic Advances, and Evolving Treatment Paradigms.
Sadaria R. · 2026-06-19
open access unreviewed -
5
Sustainable Water Remediation Through Degradation of Organic Pollutants Using Green‐Synthesized Cerium and Sulfur‐Doped TiO2 Nanoparticles
Ullah F, Saifullah J, Rasheed S, Gul S, Sharif S, Abbas S, Khan M. · 2026-10-01
open access unreviewed -
6
Determination of Gene-Level Fitness Contributions Across the Mucin-Utilization Network of Bacteroides thetaiotaomicron.
Kim K, Lee J, Kang M, Yim SS, Choe D, Cho BK. · 2026-10-04
open access unreviewed -
7
Decoding the metabolic‑immune crosstalk: The role of glutamine and ammonium reprogramming in prostate cancer immune evasion (Review).
Wang P, Li X, Ma T, Mi J. · 2026-08-28
open access unreviewed -
8
Gene variants associated with pediatric-onset erythromelalgia: Mendelian and rare-variant association analyses.
Yonas MC, Ocay DD, Genetti CA, Lobo K, Fernandes M, Groussis N, Halpin M, Wilder RT, Yu TW, Berde CB, Brownst… · 2026-08-03
open access unreviewed -
9
Integrating single-cell and bulk transcriptomics to identify a SUMOylation-related prognostic signature and the oncogenic role of VPS72 in hepatocellular carcinoma.
Li S, Wang J, Wang L, Bian T, Qian S, Zhu X, Zhou X, Wang Z, Chen L. · 2026-07-28
open access unreviewed - 10
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