What is the logic behind high levels of arginine positively regulating N-acetylglutamate synthase?
Best insight from top research papers
High levels of arginine positively regulate N-acetylglutamate synthase (NAGS) by acting as an allosteric activator. In mammals, NAGS catalyzes the formation of N-acetylglutamate (NAG), an essential activator of carbamylphosphate synthetase I (CPSI) in the urea cycle. Arginine activates mammalian NAGS, leading to increased enzymatic activity, crucial for efficient ureagenesis and ammonia detoxification. This positive regulation is highlighted by the fact that mutations in NAGS that abolish arginine binding result in hyperammonemia, emphasizing the essential role of arginine in normal ureagenesis. The evolutionary transition from arginine inhibiting bacterial NAGS to activating mammalian NAGS underscores the significance of arginine in the adaptation of animals to terrestrial environments. Therefore, the high levels of arginine positively regulate NAGS to ensure proper functioning of the urea cycle and ammonia detoxification processes.
Answers from top 5 papers
More filters
| Papers (5) | Insight |
|---|---|
| Arginine activates N-acetylglutamate synthase (NAGS) by doubling its activity, essential for normal ureagenesis. Lack of arginine binding impairs NAGS function, leading to hyperammonemia. | |
| The transition from arginine inhibition to activation of N-acetylglutamate synthase likely evolved gradually, coinciding with the terrestrial adaptation of tetrapods, indicating a shift in allosteric regulation mechanisms. | |
3 Citations | L-arginine activates N-acetylglutamate synthase (NAGS) by binding to it, essential for normal ureagenesis. This activation is crucial for converting ammonia to urea in the urea cycle. |
26 Citations | High arginine levels positively regulate N-acetylglutamate synthetase by inducing a modification in the enzyme molecule, enhancing its sensitivity to arginine activation, contributing to urea biosynthesis control in the liver. |
| High levels of arginine positively regulate N-acetylglutamate synthase by increasing thermal stability and affecting oligomerization, potentially influencing the enzyme's structure and function. |
Related Questions
What is the dual role of arginine in the urea cycle?5 answersArginine plays a dual role in the urea cycle. Firstly, it serves as a precursor for urea production in the liver and intestine, catalyzed by arginase enzymes. Secondly, arginine is involved in the detoxification of ammonia and the synthesis of ornithine, which is crucial for the production of polyamines essential for cell proliferation and wound healing. Additionally, in conditions like Arginase 1 Deficiency (ARG1-D), where there is reduced expression of urea cycle genes, arginine levels can be elevated, contributing to disease progression. This dual functionality of arginine highlights its importance in both metabolic processes and cellular functions within the urea cycle.
How does arginine affect weight gain?4 answersArginine has been shown to have an effect on weight gain in various studies. In rainbow trout, dietary arginine supplementation resulted in increased weight gain rate, specific growth rate, and protein efficiency ratio. In swine, arginine supplementation increased body weight gain and decreased carcass fat content. In mice, arginine supplementation decreased weight gain and blood glucose levels in obese mice. In rats, arginine supplementation reduced white fat pad weights and increased muscle weights. These findings suggest that arginine promotes muscle gain and reduces fat deposition, leading to improved weight gain and body composition.
What is the mechanism of niacin's raising HDL level ?3 answersNiacin raises HDL levels through multiple mechanisms. It enhances lipid efflux by increasing the transcription of the ABCA1 gene, which is involved in the formation of HDL particles. Niacin also reduces the clearance of HDL cholesterol by decreasing its plasma clearance. Additionally, niacin decreases the hepatic expression of CETP, a protein involved in HDL metabolism, leading to an increase in HDL cholesterol. These combined effects result in an increase in HDL cholesterol levels and the stabilization of newly synthesized circulating HDL particles.
What is the results of upregulation of Aminoacyl-tRNA synthetases?5 answersUpregulation of Aminoacyl-tRNA synthetases (ARSs) has been shown to have various effects. Some ARSs, such as Phenylalanyl tRNA synthetase (PheRS/FARS), have been found to be elevated in multiple cancers compared to normal cells, and their upregulation stimulates cell growth and proliferation. Additionally, many ARSs have noncanonical functions unrelated to their catalytic activity in protein synthesis. Some ARSs, including GluProRS, LeuRS, LysRS, SerRS, TyrRS, and TrpRS, exhibit cell signaling-related activities that sense environmental signals, regulate gene expression, and modulate cellular functions. Furthermore, alterations in the quality control mechanisms of ARSs can facilitate adaptation to stress conditions. Overall, upregulation of ARSs can have significant effects on cell growth, proliferation, and cellular functions, both in normal and disease states.
Is there amino acid arginine in whey?5 answersYes, whey protein contains the amino acid arginine. The whey protein hydrolysate provided in one of the papers is specifically described as being rich in arginine. Another paper mentions the use of arginine and whey protein hydrolysates for prevention and treatment of fatty liver disease in mink. Additionally, a study on milk protein response in cows found that a deficiency of arginine had a negative effect on milk protein production. Furthermore, a study on lactic acid bacteria strains found that some strains are capable of synthesizing arginine. Therefore, it can be concluded that arginine is present in whey protein and has various biological effects.
How does arginine metabolism works during oxidative stress?3 answersDuring oxidative stress, arginine metabolism plays a crucial role in maintaining cellular homeostasis and protecting against oxidative damage. Arginine is involved in the antioxidant defenses of Salmonella by preserving pH homeostasis. In patients with cardiomyopathy, oral administration of L-arginine improves intracellular redox status and regulates blood flow, attenuating oxidative stress conditions. Arginine supplementation in piglets under oxidative stress enhances the metabolism of arginine, suppresses inflammatory cytokine expression, and improves intestinal morphology. Hyperbaric oxygenation increases arginine levels and decreases arginase activity, favoring nitric oxide generation. Diquat-induced oxidative stress in post-weaning pigs affects arginine absorption and metabolism, modifying the requirement of arginine. Overall, arginine metabolism during oxidative stress involves maintaining pH homeostasis, regulating blood flow, suppressing inflammation, and influencing antioxidant defenses.