scholarly journals Review of Lysine Metabolism with a Focus on Humans

2020 ◽  
Vol 150 (Supplement_1) ◽  
pp. 2548S-2555S
Author(s):  
Dwight E Matthews
Keyword(s):  
Amino Acid ◽  
Intestinal Microflora ◽  
Food Sources ◽  
Deficient Diet ◽  
Indispensable Amino Acid ◽  
15N Urea ◽  
Lysine Catabolism ◽  
Abundant Amino Acid ◽  
Lysine Metabolism

ABSTRACT Lysine cannot be synthesized by most higher organisms and, therefore, is an indispensable amino acid (IAA) that must be consumed in adequate amounts to maintain protein synthesis. Although lysine is an abundant amino acid in body proteins, lysine is limited in abundance in many important food sources (e.g. grains). Older observations assigned importance to lysine because animals fed a lysine-deficient diet did not lose weight as fast as animals placed upon other IAA-deficient diets, leading to the theory that there may be a special pool of lysine or metabolites that could be converted to lysine. The first step in the lysine catabolic pathway is the formation of saccharopine and then 2-aminoadipic acid, processes that are mitochondrial. The catabolism of 2-aminoadipic acid proceeds via decarboxylation to a series of CoA esters ending in acetyl-CoA. In mammals, the liver appears to be the primary site of lysine catabolism. In humans, the metabolic and oxidative response of lysine to diets either restricted in protein or in lysine is consistent with what has been measured for other IAAs with isotopically labeled tracers. Intestinal microflora are known to metabolize urea to ammonia and scavenge nitrogen (N) for the synthesis of amino acids. Studies feeding 15N-ammonium chloride or 15N-urea to animals and to humans, demonstrate the appearance of 15N-lysine in gut microbial lysine and in host lysine. However, the amount of 15N-lysine transferred to the host is difficult to assess directly using current methods. It is important to understand the role of the gut microflora in human lysine metabolism, especially in conditions where dietary lysine intake may be limited, but better methods need to be devised.

scholarly journals Hypothalamic signaling in anorexia induced by indispensable amino acid deficiency

2012 ◽  
Vol 303 (12) ◽  
pp. E1446-E1458 ◽  
Author(s):  
Xinxia Zhu ◽  
Stephanie M. Krasnow ◽  
Quinn R. Roth-Carter ◽  
Peter R. Levasseur ◽  
Theodore P. Braun ◽  
...  
Keyword(s):  
Gene Expression ◽  
Adipose Tissue ◽  
Amino Acid ◽  
Food Intake ◽  
Molecular Mechanisms ◽  
Uncoupling Protein ◽  
Deficient Diet ◽  
Indispensable Amino Acid ◽  
Brown Adipose ◽  
Melanocortin Signaling

Animals exhibit a rapid and sustained anorexia when fed a diet that is deficient in a single indispensable amino acid (IAA). The chemosensor for IAA deficiency resides within the anterior piriform cortex (APC). Although the cellular and molecular mechanisms by which the APC detects IAA deficiency are well established, the efferent neural pathways that reduce feeding in response to an IAA-deficient diet remain to be fully characterized. In the present work, we investigated whether 1) central melanocortin signaling is involved in IAA deficiency-induced anorexia (IAADA) and 2) IAADA engages other key appetite-regulating neuronal populations in the hypothalamus. Rats and mice that consumed a valine-deficient diet (VDD) for 2–3 wk exhibited marked reductions in food intake, body weight, fat and lean body mass, body temperature, and white adipose tissue leptin gene expression, as well as a paradoxical increase in brown adipose tissue uncoupling protein-1 mRNA. Animals consuming the VDD had altered hypothalamic gene expression, typical of starvation. Pharmacological and genetic blockade of central melanocortin signaling failed to increase long-term food intake in this model. Chronic IAA deficiency was associated with a marked upregulation of corticotropin-releasing hormone expression in the lateral hypothalamus, particularly in the parasubthalamic nucleus, an area heavily innervated by efferent projections from the APC. Our observations indicate that the hypothalamic melanocortin system plays a minor role in acute, but not chronic, IAADA and suggest that the restraint on feeding is analogous to that observed after chronic dehydration.

scholarly journals Tryptophan requirements in small, medium, and large breed adult dogs using the indicator amino acid oxidation technique1

2019 ◽  
Vol 97 (8) ◽  
pp. 3274-3285 ◽  
Author(s):  
James R Templeman ◽  
Wilfredo D Mansilla ◽  
Lisa Fortener ◽  
Anna K Shoveller
Keyword(s):  
Amino Acid ◽  
Dry Matter ◽  
Basal Diet ◽  
Acid Oxidation ◽  
Total Production ◽  
Deficient Diet ◽  
Study Objective ◽  
Amino Acid Oxidation ◽  
Indispensable Amino Acid ◽  
Labrador Retrievers

Abstract Tryptophan (Trp) is an indispensable amino acid (AA) for dogs of all life stages; however, although Trp requirements for growing dogs are derived from 3 dose–response studies, there are no empirical data on Trp requirements for adult dogs at maintenance. The study objective was to determine Trp requirements of adult dogs of 3 different breeds using the indicator amino acid oxidation (IAAO) technique. Four spayed or neutered Miniature Dachshunds (5.28 ± 0.29 kg BW), 4 spayed Beagles (9.32 ± 0.41 kg BW), and 5 neutered Labrador Retrievers (30.51 ± 2.09 kg BW) were used. After a 14-d adaptation to a Trp-adequate basal diet (Trp = 0.482% dry matter), all dogs were fed a mildly Trp-deficient diet for 2 d (Trp = 0.092% dry matter) before being randomly allocated to receiving 1 of 7 concentrations of Trp supplementation (final Trp content in experimental diets was 0.092, 0.126, 0.148, 0.182, 0.216, 0.249, and 0.283% dry matter) and all dogs received all Trp treatments. After 2-d adaptation to the experimental diets, dogs underwent individual IAAO studies. Total feed was divided in 13 equal meals; at the sixth meal, dogs were fed a bolus of L-[1-13C]-Phenylalanine (Phe) (9.40 mg/kg BW), and thereafter, L-[1-13C]-Phe was supplied (2.4 mg/kg BW) with every meal. Total production of 13CO2 during isotopic steady state was determined by enrichment of 13CO2 in breath samples and total production of CO2 measured using indirect calorimetry. The maintenance requirement for Trp and the 95% confidence interval (CI) were determined using a 2-phase linear regression model. Mean Trp requirements were estimated at 0.154, 0.218, and 0.157% (dry-matter) for Dachshunds, Beagles, and Labradors, respectively. The upper 95% CI were 0.187, 0.269, and 0.204% (dry-matter) for Dachshunds, Beagles, and Labradors. In conclusion, estimated Trp requirements are higher for Beagles compared with Labradors or Dachshunds, and all estimated requirements are higher than those currently recommended by the NRC and AAFCO.

Role of MAP kinase in signaling indispensable amino acid deficiency in the brain

2002 ◽  
Vol 105 (1-2) ◽  
pp. 11-18 ◽  
Author(s):  
James W Sharp ◽  
Linda J Magrum ◽  
Dorothy W Gietzen
Keyword(s):  
Amino Acid ◽  
Map Kinase ◽  
Amino Acid Deficiency ◽  
Indispensable Amino Acid ◽  
Acid Deficiency ◽  
The Brain

scholarly journals Amino acid metabolism in the piglet

1976 ◽  
Vol 36 (3) ◽  
pp. 369-380 ◽  
Author(s):  
E. R. Chavez ◽  
H. S. Bayley
Keyword(s):  
Amino Acid ◽  
Plasma Concentrations ◽  
Marked Change ◽  
Experimental Period ◽  
Carbon Dioxide Production ◽  
Deficient Diet ◽  
Protein Nitrogen ◽  
Limiting Amino Acid ◽  
The Relationship ◽  
Lysine Catabolism

1. Supplementing a lysine-deficient diet (5 g lysine/kg) with five increments of lysine, each of 2 g/kg, resulted in increases in growth rate of Yorkshire piglets, aged between 3 and 7 weeks, up to the highest level of lysine (15 g/kg).2. The free lysine concentration of plasma tended to increase as the dietary lysine level increased from 13 to 15 g/kg, and plasma threonine concentration decreased significantly as the lysine content of the diet was increased from 11 to 15 g/kg indicating that threonine was the second limiting amino acid in the diet.3. Oxygen consumption and carbon dioxide production of the piglets were not influenced by supplementing the diets with lysine. The heat production was 0.313 kJ/min per kg body-weight in the 6 h experimental period.4. Supplementation of the diet with lysine had no consistent effect on the recovery of 14C as 14CO2 from a single dose of l-[U-14C]lysine.5. Adjustment of the determined recoveries of the tracer dose of lysine for the differences in the plasma concentrations of free lysine for the pigs receiving the graded levels of dietary lysine simplified the relationship between recovery and dietary lysine level: it was linear for the first four increments in dietary lysine and then increased sharply for the fifth increment. This indicated that a marked change in the rate of lysine catabolism occurred as the level of dietary lysine was increased from 13 to 15 g/kg.6. The results of this experiment indicate that the piglets' requirement for lysine is between 13 and 15 g lysine/kg in a diet which contained 181 g crude protein (nitrogen × 6.25)/kg.

scholarly journals Proteome Mining of Sortase A Dependent Proteins (SDPs) in Lactic Acid Bacteria and Docking Analysis of SDPs interaction with Sortase A

2020 ◽  
Author(s):  
Nahid Javanshir ◽  
Ehsaneh Moslem Rezvani ◽  
Zakie Mazhary ◽  
Sepideh Razani ◽  
Gholamreza Ahmadian ◽  
...  
Keyword(s):  
Amino Acid ◽  
Binding Energy ◽  
Surface Proteins ◽  
Sortase A ◽  
Docking Analysis ◽  
Bacterial Surface ◽  
Host Interaction ◽  
Tract Disorder ◽  
Abundant Amino Acid

Abstract BackgroundLactic acid bacteria (LAB), which are important probiotics, play a fundamental role in ensuring the health of the gastrointestinal tract, maintaining the microbiome balance, and preventing the gastrointestinal (GI) tract disorder. One of the effective mechanisms in the bacterial-host interaction is related to the action of the enzyme sortase A and Sortase Dependent Proteins (SDPs). Sortase plays an important role in the stabilization and retention of the probiotic in the gut by exposing various SDPs on the bacterial surface proteins which is involved in the attachment of bacteria to the host intestine and retention in the gut.ResultsIn this study, out of 165 LABs reference proteomes, there were 25 SDP-free strains. Among the 140 strains with SDPs, 707 proteins were found with the potential to function as SDPs. In this way, ProtScreen software with the ability to recognize a specific motif and domain in the proteome, which is available at http://nigebprotscreen.com/ was designed. Also a database including 707 SDPs in Lactobacillus, Enterococcus, Lactococcus, Carnobacterium, and Leuconostoc strains was designed which is available in the project section at online ProtScreen software. Our results showed that the most abundant amino acid in X position in the LPXTG motif among 165(LABs) is glutamine (Q). Results of SDPs and sortase A docking using HADDOCK and CABS-dock tools, showed that the highest binding energy is related to the glutamine, where a positive relationship between frequency of amino acids and binding energy was observed. Therefore, our data shows that why glutamine in nature and during evolution, has been selected as the best amino acid for X site in LPXTG motif.ConclusionsThe results of the present research and similar studies could be useful in better understanding the role of sortase A and SDPs in the studies on the mechanisms related to the interactions between bacteria and the host, including longer probiotic persistence in the gut.

scholarly journals Criteria and markers for protein quality assessment – a review

2012 ◽  
Vol 108 (S2) ◽  
pp. S222-S229 ◽  
Author(s):  
Daniel Tome
Keyword(s):  
Amino Acid ◽  
Nitrogen Balance ◽  
Protein Quality ◽  
The Body ◽  
Food Sources ◽  
Whole Body ◽  
Protein Nitrogen ◽  
Protein Requirements ◽  
Indispensable Amino Acid ◽  
Body Level

Dietary proteins are found in animal products, plant products and single-cell organisms. Proteins are present in variable proportions in these different food sources and the different proteins also differ in their amino acid composition, dietary indispensable amino acid content and physico-chemical properties. Different criteria can be used to define dietary protein requirements and different markers can be used to assess nutritional protein quality according to the criteria used for protein requirement estimation. The current approach to determining protein requirements is related to nitrogen balance and the dietary indispensable amino acid score approach relates protein quality to the capacity of protein to allow reaching nitrogen balance by providing nitrogen and indispensable amino acids. A second approach considers more directly protein nitrogen utilization by the body and includes measurement of protein digestibility and of the efficiency of dietary nitrogen retention at maintenance or for protein deposition at the whole body level or in more specific body areas. Another approach is related to protein turnover and protein synthesis in relation to maintenance and/or efficiency for deposition or development (growth) at the whole body level or for different and more specific target tissues such as muscle or bone. Lastly, protein quality can also be evaluated from different markers used as risk factors for metabolic dysfunction and disorders related for instance to insulin resistance, diabetes and obesity or cardio-vascular disease. The accuracy and relevance of these different approaches is discussed regarding the capacity of the different protein sources (i.e. animal as meat, milk or eggs, legume as soya or pea, or cereal as wheat or rice) to satisfy protein requirements according to these different criteria and markers.

An ESR study of the peroxidase reaction catalyzed by human methaemoglobin and methaemoglobin-haptoglobin complex

1991 ◽  
Vol 56 (4) ◽  
pp. 923-932
Author(s):  
Jana Stejskalová ◽  
Pavel Stopka ◽  
Zdeněk Pavlíček
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Amino Acid ◽  
Peroxidase Activity ◽  
Amino Acid Analysis ◽  
Superoxide Radical ◽  
Esr Spectra ◽  
The Other ◽  
Delocalized Electron

The ESR spectra of peroxidase systems of methaemoglobin-ascorbic acid-hydrogen peroxide and methaemoglobin-haptoglobin complex-ascorbic acid-hydrogen peroxide have been measured in the acetate buffer of pH 4.5. For the system with methaemoglobin an asymmetrical signal with g ~ 2 has been observed which is interpreted as the perpendicular region of anisotropic spectrum of superoxide radical. On the other hand, for the system with methaemoglobin-haptoglobin complex the observed signal with g ~ 2 is symmetrical and is interpreted as a signal of delocalized electron. After realization of three repeatedly induced peroxidase processes the ESR signal of the perpendicular part of anisotropic spectrum of superoxide radical is distinctly diminished, whereas the signal of delocalized electron remains practically unchanged. An amino acid analysis of methaemoglobin along with results of the ESR measurements make it possible to derive a hypothesis about the role of haptoglobin in increasing of the peroxidase activity of methaemoglobin.

10 THE ROLE OF DIETARY L-SERINE IN THE REGULATION OF INTESTINAL MUCUS BARRIER DURING INFLAMMATION

2020 ◽  
Vol 26 (Supplement_1) ◽  
pp. S42-S42
Author(s):  
Kohei Sugihara ◽  
Nobuhiko Kamada
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Gut Microbiota ◽  
Control Diet ◽  
Bacterial Strains ◽  
Germ Free ◽  
Intestinal Mucus ◽  
Gnotobiotic Mice ◽  
Mucus Barrier

Abstract Background Recent accumulating evidence suggests that amino acids have crucial roles in the maintenance of intestinal homeostasis. In inflammatory bowel disease (IBD), amino acid metabolism is changed in both host and the gut microbiota. Among amino acids, L-serine plays a central role in several metabolic processes that are essential for the growth and survival of both mammalian and bacterial cells. However, the role of L-serine in intestinal homeostasis and IBD remains incompletely understood. In this study, we investigated the effect of dietary L-serine on intestinal inflammation in a murine model of colitis. Methods Specific pathogen-free (SPF) mice were fed either a control diet (amino acid-based diet) or an L-serine-deficient diet (SDD). Colitis was induced by the treatment of dextran sodium sulfate (DSS). The gut microbiome was analyzed by 16S rRNA sequencing. We also evaluate the effect of dietary L-serine in germ-free mice and gnotobiotic mice that were colonized by a consortium of non-mucolytic bacterial strains or the consortium plus mucolytic bacterial strains. Results We found that the SDD exacerbated experimental colitis in SPF mice. However, the severity of colitis in SDD-fed mice was comparable to control diet-fed mice in germ-free condition, suggesting that the gut microbiota is required for exacerbation of colitis caused by the restriction of dietary L-serine. The gut microbiome analysis revealed that dietary L-serine restriction fosters the blooms of a mucus-degrading bacterium Akkermansia muciniphila and adherent-invasive Escherichia coli in the inflamed gut. Consistent with the expansion of mucolytic bacteria, SDD-fed mice showed a loss of the intestinal mucus layer. Dysfunction of the mucus barrier resulted in increased intestinal permeability, thereby leading to bacterial translocation to the intestinal mucosa, which subsequently increased the severity of colitis. The increased intestinal permeability and subsequent bacterial translocation were observed in SDD-fed gnotobiotic mice that colonized by mucolytic bacteria. In contrast, dietary L-serine restriction did not alter intestinal barrier integrity in gnotobiotic mice that colonized only by non-mucolytic bacteria. Conclusion Our results suggest that dietary L-serine regulates the integrity of the intestinal mucus barrier during inflammation by limiting the expansion of mucus degrading bacteria.

Sign in / Sign up

Export Citation Format

Share Document