Branched chain amino acids stimulate gut satiety hormone cholecystokinin secretion through activation of the umami taste receptor T1R1/T1R3 using an in vitro porcine jejunum model

2019 ◽  
Vol 10 (6) ◽  
pp. 3356-3367 ◽  
Author(s):  
Min Tian ◽  
Jinghui Heng ◽  
Hanqing Song ◽  
Yufeng Zhang ◽  
Fang Chen ◽  
...  

Branched chain amino acids (BCAAs) modulate the intestinal CCK secretion through the T1R1/ T1R3 amino acid receptor.

2018 ◽  
Vol 115 (25) ◽  
pp. 6446-6451 ◽  
Author(s):  
Mingxu Fang ◽  
Carl E. Bauer

When faced with amino acid starvation, prokaryotic cells induce a stringent response that modulates their physiology. The stringent response is manifested by production of signaling molecules guanosine 5′-diphosphate,3′-diphosphate (ppGpp) and guanosine 5′-triphosphate,3′-diphosphate (pppGpp) that are also called alarmones. In many species, alarmone levels are regulated by a multidomain bifunctional alarmone synthetase/hydrolase called Rel. In this enzyme, there is an ACT domain at the carboxyl region that has an unknown function; however, similar ACT domains are present in other enzymes that have roles in controlling amino acid metabolism. In many cases, these other ACT domains have been shown to allosterically regulate enzyme activity through the binding of amino acids. Here, we show that the ACT domain present in theRhodobacter capsulatusRel alarmone synthetase/hydrolase binds branched-chain amino acids valine and isoleucine. We further show that the binding of these amino acids stimulates alarmone hydrolase activity both in vitro and in vivo. Furthermore, we found that the ACT domain present in Rel proteins from many diverse species also binds branched-chain amino acids. These results indicate that the cellular concentration of amino acids can directly affect Rel alarmone synthetase/hydrolase activity, thus adding another layer of control to current models of cellular control of the stringent response.


Microbiology ◽  
2009 ◽  
Vol 155 (9) ◽  
pp. 2978-2987 ◽  
Author(s):  
Disha Awasthy ◽  
Sheshagiri Gaonkar ◽  
R. K. Shandil ◽  
Reena Yadav ◽  
Sowmya Bharath ◽  
...  

Acetohydroxyacid synthase (AHAS) is the first enzyme in the branched-chain amino acid biosynthesis pathway in bacteria. Bioinformatics analysis revealed that the Mycobacterium tuberculosis genome contains four genes (ilvB1, ilvB2, ilvG and ilvX) coding for the large catalytic subunit of AHAS, whereas only one gene (ilvN or ilvH) coding for the smaller regulatory subunit of this enzyme was found. In order to understand the physiological role of AHAS in survival of the organism in vitro and in vivo, we inactivated the ilvB1 gene of M. tuberculosis. The mutant strain was found to be auxotrophic for all of the three branched-chain amino acids (isoleucine, leucine and valine), when grown with either C6 or C2 carbon sources, suggesting that the ilvB1 gene product is the major AHAS in M. tuberculosis. Depletion of these branched chain amino acids in the medium led to loss of viability of the ΔilvB1 strain in vitro, resulting in a 4-log reduction in colony-forming units after 10 days. Survival kinetics of the mutant strain cultured in macrophages maintained with sub-optimal concentrations of the branched-chain amino acids did not show any loss of viability, indicating either that the intracellular environment was rich in these amino acids or that the other AHAS catalytic subunits were functional under these conditions. Furthermore, the growth kinetics of the ΔilvB1 strain in mice indicated that although this mutant strain showed defective growth in vivo, it could persist in the infected mice for a long time, and therefore could be a potential vaccine candidate.


Author(s):  
Moath Alqaraleh ◽  
Violet Kasabri ◽  
Ibrahim Al-Majali ◽  
Nihad Al-Othman ◽  
Nihad Al-Othman ◽  
...  

Background and aims: Branched chain amino acids (BCAAs) can be tightly connected to metabolism syndrome (MetS) which can be counted as a metabolic indicator in the case of insulin resistance (IR). The aim of this study was to assess the potential role of these acids under oxidative stress. Material and Methods: the in vitro antioxidant activity of BCAAs was assessed using free radical 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) scavenging assays. For further check, a qRT-PCR technique was madefor detection the extent of alterations in gene expression of antioxidative enzymes (catalase and glutathione peroxidase (Gpx)) in lipopolysaccharides (LPS(-induced macrophages RAW 264.7 cell line. Additionally, BCAAs antioxidant activity was evaluated based on plasma H2O2 levels and xanthine oxidase (XO) activity in prooxidative LPS-treated mice. Results: Different concentrations of BCAAs affected on DPPH radical scavenging activity but to lesser extent than the ascorbic acid. Besides, BCAAs obviously upregulated the gene expression levels of catalases and Gpx in LPS-modulated macrophage RAW 264.7 cell line. In vivo BCAAs significantly minimized the level of plasma H2O2 as well as the activity of XO activity under oxidative stress. Conclusion: our current findings suggest that BCAAs supplementation may potentially serve as a therapeutic target for treatment of oxidative stress occurs with atherosclerosis, IR-diabetes, MetS and tumorigenesis.


1990 ◽  
Vol 73 (3A) ◽  
pp. NA-NA
Author(s):  
H. Yamada ◽  
Y. Ohta ◽  
I. Chaudhry ◽  
H. Nagashima ◽  
J. Askanazi ◽  
...  

1983 ◽  
Vol 6 (5) ◽  
pp. 267-270 ◽  
Author(s):  
Z.Q. Shi ◽  
T.M.S. Chang

In order to clarify wether coated charcoal hemoperfusion is capable of normalizing amino acid disturbances in hepatic coma, in vitro adsorption and in vitro hemoperfusion studies were carried out. We have found that collodion-coated activated charcoal beads preferentially removed much more aromatic acids (AAA) than branched chain amino acids (BCAA). In the in vitro adsorption experiment with 50 μM amino acid standards aqueous solution, 99% of AAAs were removed by charcoal while only 50 to 81% of BCAAs were removed. As the concentration of amino acids in solution was doubled from μM to 100 μM, BCAA removal was halved while about 90% of AAA was still being removed. In vitro hemoperfusion with heparinized blood from hepatic failure rats, the clearance and the removal of AAAs were significantly greater than those of BCAAs. Consequently, the molar ratio of BCAA over AAA was markedly improved from the initial 1.09 to 3.87 after 60 min of hemoperfusion. Thus, we have demonstrated the preferential adsorption of aromatic amino acids by collodion-coated charcoal beads. The correction of BCAA/AAA molar ratio is also demonstrated.


1986 ◽  
Vol 250 (4) ◽  
pp. E407-E413 ◽  
Author(s):  
R. A. Gelfand ◽  
M. G. Glickman ◽  
R. Jacob ◽  
R. S. Sherwin ◽  
R. A. DeFronzo

To compare the contributions of splanchnic and skeletal muscle tissues to the disposal of intravenously administered amino acids, regional amino acid exchange was measured across the splanchnic bed and leg in 11 normal volunteers. Postabsorptively, net release of amino acids by leg (largely alanine and glutamine) was complemented by the net splanchnic uptake of amino acids. Amino acid infusion via peripheral vein (0.2 g X kg-1 X h-1) caused a doubling of plasma insulin and glucagon levels and a threefold rise in blood amino acid concentrations. Both splanchnic and leg tissues showed significant uptake of infused amino acids. Splanchnic tissues accounted for approximately 70% of the total body amino acid nitrogen disposal; splanchnic uptake was greatest for the glucogenic amino acids but also included significant quantities of branched-chain amino acids. In contrast, leg amino acid uptake was dominated by the branched-chain amino acids. Based on the measured leg balance, body skeletal muscle was estimated to remove approximately 25-30% of the total infused amino acid load and approximately 65-70% of the infused branched-chain amino acids. Amino acid infusion significantly stimulated both the leg efflux and the splanchnic uptake of glutamine (not contained in the infusate). We conclude that when amino acids are infused peripherally in normal humans, splanchnic viscera (liver and gut) are the major sites of amino acid disposal.


2008 ◽  
Vol 190 (18) ◽  
pp. 6134-6147 ◽  
Author(s):  
Shigeo Tojo ◽  
Takenori Satomura ◽  
Kanako Kumamoto ◽  
Kazutake Hirooka ◽  
Yasutaro Fujita

ABSTRACT Branched-chain amino acids are the most abundant amino acids in proteins. The Bacillus subtilis ilv-leu operon is involved in the biosynthesis of branched-chain amino acids. This operon exhibits a RelA-dependent positive stringent response to amino acid starvation. We investigated this positive stringent response upon lysine starvation as well as decoyinine treatment. Deletion analysis involving various lacZ fusions revealed two molecular mechanisms underlying the positive stringent response of ilv-leu, i.e., CodY-dependent and -independent mechanisms. The former is most likely triggered by the decrease in the in vivo concentration of GTP upon lysine starvation, GTP being a corepressor of the CodY protein. So, the GTP decrease derepressed ilv-leu expression through detachment of the CodY protein from its cis elements upstream of the ilv-leu promoter. By means of base substitution and in vitro transcription analyses, the latter (CodY-independent) mechanism was found to comprise the modulation of the transcription initiation frequency, which likely depends on fluctuation of the in vivo RNA polymerase substrate concentrations after stringent treatment, and to involve at least the base species of adenine at the 5′ end of the ilv-leu transcript. As discussed, this mechanism is presumably distinct from that for B. subtilis rrn operons, which involves changes in the in vivo concentration of the initiating GTP.


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