scholarly journals Hyperammonemia due to N-acetylglutamate synthase deficiency

2020 ◽  
Author(s):  
Keyword(s):  
Acetylglutamate Synthase

scholarly journals Interaction of Excitatory Amino Acid Transporters 1 – 3 (EAAT1, EAAT2, EAAT3) with N-Carbamoylglutamate and N-Acetylglutamate

2017 ◽  
Vol 43 (5) ◽  
pp. 1907-1916 ◽  
Author(s):  
Birgitta C. Burckhardt ◽  
Gerhard Burckhardt
Keyword(s):  
Amino Acid ◽  
Excitatory Amino Acid ◽  
Hepatic Uptake ◽  
Xenopus Laevis Oocytes ◽  
Amino Acid Transporters ◽  
Synthetic Analog ◽  
Excitatory Amino Acid Transporters ◽  
Sodium Dependent ◽  
Inward Currents ◽  
Acetylglutamate Synthase

Background/Aims: Inborn deficiency of the N-acetylglutamate synthase (NAGS) impairs the urea cycle and causes neurotoxic hyperammonemia. Oral administration of N-carbamoylglutamate (NCG), a synthetic analog of N-acetylglutamate (NAG), successfully decreases plasma ammonia levels in the affected children. Due to structural similarities to glutamate, NCG may be absorbed in the intestine and taken up into the liver by excitatory amino acid transporters (EAATs). Methods: Using Xenopus laevis oocytes expressing either human EAAT1, 2, or 3, or human sodium-dependent dicarboxylate transporter 3 (NaDC3), transport-associated currents of NAG, NCG, and related dicarboxylates were assayed. Results: L-aspartate and L-glutamate produced saturable inward currents with Km values below 30 µM. Whereas NCG induced a small inward current only in EAAT3 expressing oocytes, NAG was accepted by all EAATs. With EAAT3, the NAG-induced current was sodium-dependent and saturable (Km 409 µM). Oxaloacetate was found as an additional substrate of EAAT3. In NaDC3-expressing oocytes, all dicarboxylates induced much larger inward currents than did L-aspartate and L-glutamate. Conclusion: EAAT3 may contribute to intestinal absorption and hepatic uptake of NCG. With respect to transport of amino acids and dicarboxylates, EAAT3 and NaDC3 can complement each other.

scholarly journals Acute effects of glucagon on citrulline biosynthesis

1982 ◽  
Vol 206 (3) ◽  
pp. 627-631 ◽  
Author(s):  
D Rabier ◽  
P Briand ◽  
F Petit ◽  
P Parvy ◽  
P Kamoun ◽  
...  
Keyword(s):  
High Protein Diet ◽  
High Protein ◽  
Protein Diet ◽  
Carbamoyl Phosphate Synthetase ◽  
Acute Effects ◽  
Carbamoyl Phosphate ◽  
Carbohydrate Diet ◽  
Acetylglutamate Synthase

Mitochondria isolated from livers of rats fed on different diets showed altered capacity to synthesize citrulline. Glucagon, 15 min after injection, increases citrulline biosynthesis, except after the high-protein diet. A significant correlation between citrulline biosynthesis and N-acetylglutamate content with and without glucagon treatment was shown when rats were fed on a standard or a carbohydrate diet. Different diets modified carbamoyl phosphate synthetase I (EC 6.3.4.16) and N-acetylglutamate synthase (acetyl-CoA:L-glutamate N-acetyltransferase, EC 2.3.1.1) activities. Glucagon did not modify these activities.

scholarly journals Late-Onset N-Acetylglutamate Synthase Deficiency: Report of a Paradigmatic Adult Case Presenting with Headaches and Review of the Literature

2018 ◽  
Vol 19 (2) ◽  
pp. 345
Author(s):  
Catia Cavicchi ◽  
Chiara Chilleri ◽  
Antonella Fioravanti ◽  
Lorenzo Ferri ◽  
Francesco Ripandelli ◽  
...  
Keyword(s):  
Late Onset ◽  
Review Of The Literature ◽  
Adult Case ◽  
Acetylglutamate Synthase

scholarly journals Surprising Arginine Biosynthesis: a Reappraisal of the Enzymology and Evolution of the Pathway in Microorganisms

2007 ◽  
Vol 71 (1) ◽  
pp. 36-47 ◽  
Author(s):  
Ying Xu ◽  
Bernard Labedan ◽  
Nicolas Glansdorff
Keyword(s):  
Biosynthetic Pathway ◽  
De Novo ◽  
Single Gene ◽  
Metabolic Function ◽  
Gene Products ◽  
Arginine Biosynthesis ◽  
Acetyl Coenzyme A ◽  
Bacterial Phyla ◽  
Acetyl Group ◽  
Acetylglutamate Synthase

SUMMARY Major aspects of the pathway of de novo arginine biosynthesis via acetylated intermediates in microorganisms must be revised in light of recent enzymatic and genomic investigations. The enzyme N-acetylglutamate synthase (NAGS), which used to be considered responsible for the first committed step of the pathway, is present in a limited number of bacterial phyla only and is absent from Archaea. In many Bacteria, shorter proteins related to the Gcn5-related N-acetyltransferase family appear to acetylate l-glutamate; some are clearly similar to the C-terminal, acetyl-coenzyme A (CoA) binding domain of classical NAGS, while others are more distantly related. Short NAGSs can be single gene products, as in Mycobacterium spp. and Thermus spp., or fused to the enzyme catalyzing the last step of the pathway (argininosuccinase), as in members of the Alteromonas-Vibrio group. How these proteins bind glutamate remains to be determined. In some Bacteria, a bifunctional ornithine acetyltransferase (i.e., using both acetylornithine and acetyl-CoA as donors of the acetyl group) accounts for glutamate acetylation. In many Archaea, the enzyme responsible for glutamate acetylation remains elusive, but possible connections with a novel lysine biosynthetic pathway arose recently from genomic investigations. In some Proteobacteria (notably Xanthomonadaceae) and Bacteroidetes, the carbamoylation step of the pathway appears to involve N-acetylornithine or N-succinylornithine rather than ornithine. The product N-acetylcitrulline is deacetylated by an enzyme that is also involved in the provision of ornithine from acetylornithine; this is an important metabolic function, as ornithine itself can become essential as a source of other metabolites. This review insists on the biochemical and evolutionary implications of these findings.

Glucagon receptor signaling is not required for N-carbamoyl glutamate- and l-citrulline-induced ureagenesis in mice

2020 ◽  
Vol 318 (5) ◽  
pp. G912-G927
Author(s):  
Katrine D. Galsgaard ◽  
Jens Pedersen ◽  
Sasha A. S. Kjeldsen ◽  
Marie Winther-Sørensen ◽  
Elena Stojanovska ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Urea Cycle ◽  
Receptor Signaling ◽  
Glucagon Receptor ◽  
Acetylglutamate Synthase

Hepatic ureagenesis is essential in amino acid metabolism and is importantly regulated by glucagon, but the exact mechanism is unclear. With the aim to identify the steps whereby glucagon both acutely and chronically regulates ureagenesis, we here show, contrary to our hypothesis, that glucagon receptor-mediated activation of ureagenesis is not required when N-acetylglutamate synthase activity and/or N-acetylglutamate levels are sufficient to activate the first step of the urea cycle in vivo.

scholarly journals Evolution of the Effect of Arginine on Thermal Stability and Oligomerization of N-Acetylglutamate Synthase

2011 ◽  
Vol 100 (3) ◽  
pp. 55a-56a
Author(s):  
Ljubica Caldovic ◽  
Nantaporn Haskins ◽  
Amy Mumo ◽  
Mendel Tuchman ◽  
Hiroki Morizono
Keyword(s):  
Thermal Stability ◽  
Acetylglutamate Synthase

Biochemical properties of recombinant human and mouse N-acetylglutamate synthase

2006 ◽  
Vol 87 (3) ◽  
pp. 226-232 ◽  
Author(s):  
Ljubica Caldovic ◽  
Giselle Y. Lopez ◽  
Nantaporn Haskins ◽  
Maria Panglao ◽  
Dashuang Shi ◽  
...  
Keyword(s):  
Biochemical Properties ◽  
Acetylglutamate Synthase ◽  
Human And Mouse

scholarly journals Expression Pattern and Biochemical Properties of Zebrafish N-Acetylglutamate Synthase

PLoS ONE ◽  
2014 ◽  
Vol 9 (1) ◽  
pp. e85597 ◽  
Author(s):  
Ljubica Caldovic ◽  
Nantaporn Haskins ◽  
Amy Mumo ◽  
Himani Majumdar ◽  
Mary Pinter ◽  
...  
Keyword(s):  
Expression Pattern ◽  
Biochemical Properties ◽  
Acetylglutamate Synthase
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