scholarly journals Branched-Chain Amino Acids and Branched-Chain Keto Acids in Hyperammonemic States: Metabolism and as Supplements

Metabolites ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 324 ◽  
Author(s):  
Milan Holeček
Keyword(s):  
Amino Acids ◽  
Branched Chain Amino Acids ◽  
Muscle Performance ◽  
Strenuous Exercise ◽  
Protein Balance ◽  
Keto Acids ◽  
Amino Acid Imbalance ◽  
Branched Chain ◽  
Cycle Disorders ◽  
Branched Chain Keto Acids

In hyperammonemic states, such as liver cirrhosis, urea cycle disorders, and strenuous exercise, the catabolism of branched-chain amino acids (BCAAs; leucine, isoleucine, and valine) is activated and BCAA concentrations decrease. In these conditions, BCAAs are recommended to improve mental functions, protein balance, and muscle performance. However, clinical trials have not demonstrated significant benefits of BCAA-containing supplements. It is hypothesized that, under hyperammonemic conditions, enhanced glutamine availability and decreased BCAA levels facilitate the amination of branched-chain keto acids (BCKAs; α-ketoisocaproate, α-keto-β-methylvalerate, and α-ketoisovalerate) to the corresponding BCAAs, and that BCKA supplementation may offer advantages over BCAAs. Studies examining the effects of ketoanalogues of amino acids have provided proof that subjects with hyperammonemia can effectively synthesize BCAAs from BCKAs. Unfortunately, the benefits of BCKA administration have not been clearly confirmed. The shortcoming of most reports is the use of mixtures intended for patients with renal insufficiency, which might be detrimental for patients with liver injury. It is concluded that (i) BCKA administration may decrease ammonia production, attenuate cataplerosis, correct amino acid imbalance, and improve protein balance and (ii) studies specifically investigating the effects of BCKA, without the interference of other ketoanalogues, are needed to complete the information essential for decisions regarding their suitability in hyperammonemic conditions.

Influence of branched-chain amino acids and branched-chain keto acids on protein synthesis in isolated hepatocytes

Hepatology ◽  
1987 ◽  
Vol 7 (2) ◽  
pp. 324-329 ◽  
Author(s):  
Wolfgang Base ◽  
Carl Barsigian ◽  
Alisa Schaeffer ◽  
Ellen Shaw ◽  
Jose Martinez ◽  
...  
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Isolated Hepatocytes ◽  
Branched Chain Amino Acids ◽  
Keto Acids ◽  
Branched Chain ◽  
Branched Chain Keto Acids

Transamination of branched-chain keto acids by isolated perfused rat kidney.

1978 ◽  
Vol 235 (1) ◽  
pp. E47
Author(s):  
W E Mitch ◽  
W Chan
Keyword(s):  
Amino Acids ◽  
Rat Kidney ◽  
Branched Chain Amino Acids ◽  
Keto Acid ◽  
Branched Chain Amino Acid ◽  
Keto Acids ◽  
Perfused Rat Kidney ◽  
Branched Chain ◽  
Branched Chain Keto Acids ◽  
Isolated Rat

Isolated rat kidney perfused without substrate released serine, glycine, and taurine, and substantially smaller amounts of other amino acids. When branched-chain keto acids were added, the corresponding amino acids were released at rates amounting to 15-25% of keto acid disappearance. Perfusion with 2 mM alpha-keto-isovalerate or alpha-keto-beta-methylvalerate caused an increased glucose release amounting to 18-23% of keto acid disappearance. The activity of branched-chain amino acid transferase (BATase) was significantly stimulated by perfusion with the analogue of leucine, but not by perfusion with alpha-ketoglutarate, the analogues of valine or isoleucine, or with leucine itself. These findings document that the kidney converts branched-chain keto acids in part to the corresponding amino acids and suggest that the keto analogue of leucine may be involved in the control of renal BATase activity, thereby indirectly regulating the metabolism of branched-chain amino acids.

Abstract MP125: Branched-chain Keto Acids, Not Branched-chain Amino Acids, Impairs Cardiac Insulin Sensitivity by Disrupting Insulin Signaling in the Mitochondria

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Qutuba Karwi ◽  
Golam Mezbah Uddin ◽  
Cory S Wagg ◽  
Gary D Lopaschuk
Keyword(s):  
Insulin Resistance ◽  
Amino Acids ◽  
Insulin Sensitivity ◽  
Glucose Oxidation ◽  
Branched Chain Amino Acids ◽  
Mitochondrial Translocation ◽  
Oxidation Rates ◽  
Keto Acids ◽  
Branched Chain ◽  
Branched Chain Keto Acids

Alterations in branched-chain amino acids (BCAA) oxidation have been linked to the development of cardiac insulin resistance and its negative impact on cardiac function. However, it is not clear if these detrimental effects are due to the accumulation of BCAAs or branched-chain keto acids (BCKAs). It is also unknown how impaired BCAAs oxidation mediates cardiac insulin resistance. To examine this, we specifically deleted mitochondrial branched-chain aminotransferase (BCATm) in the heart to selectively increase in BCAAs and decrease in BCKAs in the heart. BCATm -/- mice had normal cardiac function compared to their wildtype littermates (WT Cre+/+ ). However, there was a significant increase in insulin-stimulated cardiac glucose oxidation rates in BCATm -/- mice, independent of any changes in glucose uptake or glycolytic rates. This enhancement in cardiac insulin sensitivity was associated with an increase in the phosphorylation of Akt and activation of pyruvate dehydrogenase (PDH), the rate-limiting enzyme of glucose oxidation. To determine the impact of reversing these events, we examined the effects of increasing cardiac BCKAs on cardiac insulin sensitivity. We perfused isolated working mice hearts with high levels of BCKAs (α;-keto-isocaproate 80 μM, α;-keto-β;-methylvalorate 100μM, α;-keto-isovalorate 70 μM), levels that can be seen during diabetes and obesity. The BCKAs completely blunted insulin-stimulated glucose oxidation rates. We also found that BCKAs abolished insulin-stimulated mitochondrial translocation of Akt, an effect which was associated with PDH deactivation. We conclude that the accumulation of BCKAs, and not BCAAs, is a major contributor to cardiac insulin resistance via abrogating mitochondrial translocation of Akt.

scholarly journals Sodium phenylbutyrate decreases plasma branched-chain amino acids in patients with urea cycle disorders

2014 ◽  
Vol 113 (1-2) ◽  
pp. 131-135 ◽  
Author(s):  
Lindsay C. Burrage ◽  
Mahim Jain ◽  
Laura Gandolfo ◽  
Brendan H. Lee ◽  
Sandesh C.S. Nagamani
Keyword(s):  
Amino Acids ◽  
Urea Cycle ◽  
Branched Chain Amino Acids ◽  
Urea Cycle Disorders ◽  
Branched Chain ◽  
Cycle Disorders ◽  
Sodium Phenylbutyrate

scholarly journals In Vitro Transcriptional Studies of thebkd Operon of Pseudomonas putida:l-Branched-Chain Amino Acids and d-Leucine Are the Inducers

1999 ◽  
Vol 181 (9) ◽  
pp. 2889-2894 ◽  
Author(s):  
Kunapuli T. Madhusudhan ◽  
Jinhe Luo ◽  
John R. Sokatch
Keyword(s):  
Amino Acids ◽  
Transcriptional Activation ◽  
In Vitro Transcription ◽  
Branched Chain Amino Acids ◽  
Multienzyme Complex ◽  
Keto Acids ◽  
Transcription In Vitro ◽  
Branched Chain ◽  
Hydroxyl Radical Footprinting

ABSTRACT BkdR is the transcriptional activator of the bkdoperon, which encodes the four proteins of the branched-chain keto acid dehydrogenase multienzyme complex of Pseudomonas putida. In this study, hydroxyl radical footprinting revealed that BkdR bound to only one face of DNA over the same region identified in DNase I protection assays. Deletions of even a few bases in the 5′ region of the BkdR-binding site greatly reduced transcription, confirming that the entire protected region is necessary for transcription. In vitro transcription of the bkd operon was obtained by using a vector containing the bkdR-bkdA1 intergenic region plus the putative ρ-independent terminator of the bkdoperon. Substrate DNA, BkdR, and any of thel-branched-chain amino acids or d-leucine was required for transcription. Branched-chain keto acids,d-valine, and d-isoleucine did not promote transcription. Therefore, the l-branched-chain amino acids and d-leucine are the inducers of the bkdoperon. The concentration of l-valine required for half-maximal transcription was 2.8 mM, which is similar to that needed to cause half-maximal proteolysis due to a conformational change in BkdR. A model for transcriptional activation of the bkdoperon by BkdR during enzyme induction which incorporates these results is presented.

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