Journal articles: 'Catabolism of mammal amino acids'

1

Робонен (Robonen), Елена (Elena) Вильямовна (Vil'yamovna), Надежда (Nadezhda) Петровна (Petrovna) Чернобровкина (Chernobrovkina), Оксана (Oksana) Васильевна (Vasil'evna) Чернышенко (Chernyshenko), Мария (Mariya) Игоревна (Igorevna) Зайцева (Zaytseva), Алексей (Aleksey) Рудольфович (Rudol'fovich) Унжаков (Unzhakov), and Анастасия (Anastasiya) Васильевна (Vasil'evna) Егорова (Egorova). "PERSPECTIVES OF WOOD-GREENERY BIOTECHNOLOGY ENRICHMENT WITH L-ARGININE AND INHIBITORS OF ITS CATABOLISM." chemistry of plant raw material, no. 1 (March 6, 2019): 23–37. http://dx.doi.org/10.14258/jcprm.2019014243.

Full text

Abstract:

A promising source of L-arginine, as well as natural inhibitors of its catabolism enzymes, are plants. Free amino acids constitute a significant part of the water-soluble fraction of woody greenery of coniferous plants, including L-arginine. The biotechnology of L-arginine enrichment of coniferous woody greenery is developed by regulating nitrogen and boron support. The fact of a multiple increase in the pool of free L-arginine in needles suggests an increase in the level of enzyme inhibitors of its catabolism. Coniferous greens contain guanidine compounds, which are therapeutic agents for controlling the activity of nitric oxide synthases. L-arginine, one of the most universal amino acids in the metabolism of the animal body, in mammals is classified as a conditionally essential amino acid. The imbalance of the activities of the arginic and NO-synthase catabolism pathways of arginine, competing for the substrate, can lead to pathological consequences for the organism. Activation of inducible NO synthase or arginase reflects the type of inflammatory response in the development of specific diseases. In their treatment, the effectors controlling the activity of catabolism enzymes are considered as targets for pharmacological action. Examples of the use in folk medicine of extracts from some species of gymnosperms are given in the works of ethnomedical orientation. Analysis of the current state of studies of the metabolism of L-arginine in living organisms and its features in coniferous plants was carried out for the scientific substantiation of the prospects of obtaining enzymes for its metabolism of woody greens enriched with L-arginine and effector enzymes.

APA, Harvard, Vancouver, ISO, and other styles

2

Stewart, Gavin S., and Craig P. Smith. "Urea nitrogen salvage mechanisms and their relevance to ruminants, non-ruminants and man." Nutrition Research Reviews 18, no. 1 (June 2005): 49–62. http://dx.doi.org/10.1079/nrr200498.

Full text

Abstract:

AbstractMaintaining a correct balance of N is essential for life. In mammals, the major sources of N in the diet are amino acids and peptides derived from ingested proteins. The immediate endproduct of mammalian protein catabolism is ammonia, which is toxic to cells if allowed to accumulate. Therefore, amino acids are broken down in the liver as part of the ornithine–urea cycle, which results in the formation of urea – a highly soluble, biochemically benign molecule. Mammals cannot break down urea, which is traditionally viewed as a simple waste product passed out in the urine. However, urea from the bloodstream can pass into the gastrointestinal tract, where bacteria expressing urease cleave urea into ammonia and carbon dioxide. The bacteria utilise the ammonia as an N source, producing amino acids and peptides necessary for growth. Interestingly, these microbial products can be reabsorbed back into the host mammalian circulation and used for synthetic processes. This entire process is known as ‘urea nitrogen salvaging’ (UNS). In this review we present evidence supporting a role for this process in mammals – including ruminants, non-ruminants and man. We also explore the possible mechanisms involved in UNS, including the role of specialised urea transporters.

APA, Harvard, Vancouver, ISO, and other styles

3

Teleni, E. "Catabolism and synthesis of amino acids in skeletal muscle: their significance in monogastric mammals and ruminants." Australian Journal of Agricultural Research 44, no. 3 (1993): 443. http://dx.doi.org/10.1071/ar9930443.

Full text

Abstract:

The enhanced rate of synthesis and catabolism of amino acids in, and their release from, skeletal muscle, particularly during fasting, exercise and metabolic acidosis, highlight the integrative role of muscle in protein-energy metabolism. This review discusses aspects of such changes in muscles of monogastric mammals and ruminants. The glucose-alanine cycle, as it was originally proposed, has been well substantiated by studies using human and rat muscles. An alternative proposal, which suggested that other amino acids make a major contribution to the carbon skeleton of alanine synthesized in muscle, is less convincing, since some of the inhibitors and substrates used in relevant studies have been demonstrated to have multiple rather than specific effects. In the ruminant, the glucose-alanine cycle is quantitatively less significant than in human. The probable reason for this difference is the limited available pyruvate in ruminant muscle for transamination to alanine. This may be due to a lower carbon flux through the glycolytic pathway and/or to significant activity of the anaplerotic enzyme, pyruvate carboxylase. It is suggested that glutamine is the more important carrier of carbon and nitrogen out of skeletal muscle and that alanine may serve only as an ancillary vehicle to transport carbon and nitrogen when the availability of pyruvate for transamination in muscle is high. The more diverse role of glutamine (cf. alanine) in acid-base balance, as a respiratory fuel in the cells of the immune system and the epithelia of the small intestine, where it may also be converted to alanine for subsequent gluconeogenesis in the liver, is consistent with this suggestion.

APA, Harvard, Vancouver, ISO, and other styles

4

Matthews, Dwight E. "Review of Lysine Metabolism with a Focus on Humans." Journal of Nutrition 150, Supplement_1 (October 1, 2020): 2548S—2555S. http://dx.doi.org/10.1093/jn/nxaa224.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

5

Herring, Cassandra M., Fuller W. Bazer, Gregory A. Johnson, and Guoyao Wu. "Impacts of maternal dietary protein intake on fetal survival, growth, and development." Experimental Biology and Medicine 243, no. 6 (February 22, 2018): 525–33. http://dx.doi.org/10.1177/1535370218758275.

Full text

Abstract:

Maternal nutrition during gestation, especially dietary protein intake, is a key determinant in embryonic survival, growth, and development. Low maternal dietary protein intake can cause embryonic losses, intra-uterine growth restriction, and reduced postnatal growth due to a deficiency in specific amino acids that are important for cell metabolism and function. Of note, high maternal dietary protein intake can also result in intra-uterine growth restriction and embryonic death, due to amino acid excesses, as well as the toxicity of ammonia, homocysteine, and H2S that are generated from amino acid catabolism. Maternal protein nutrition has a pronounced impact on fetal programming and alters the expression of genes in the fetal genome. As a precursor to the synthesis of molecules (e.g. nitric oxide, polyamines, and creatine) with cell signaling and metabolic functions, L-arginine (Arg) is essential during pregnancy for growth and development of the conceptus. With inadequate maternal dietary protein intake, Arg and other important amino acids are deficient in mother and fetus. Dietary supplementation of Arg during gestation has been effective in improving embryonic survival and development of the conceptus in many species, including humans, pigs, sheep, mice, and rats. Both the balance among amino acids and their quantity are critical for healthy pregnancies and offspring. Impact statement This review aims at: highlighting adverse effects of elevated levels of ammonia in mother or fetus on embryonic/fetal survival, growth, and development; helping nutritionists and practitioners to understand the mechanisms whereby elevated levels of ammonia in mother or fetus results in embryonic/fetal death, growth restriction, and developmental abnormalities; and bringing, into the attention of nutritionists and practitioners, the problems of excess or inadequate dietary intake of protein or amino acids on pregnancy outcomes in animals and humans. The article provides new, effective means to improve embryonic/fetal survival and growth in mammals.

APA, Harvard, Vancouver, ISO, and other styles

6

Lobley, G. E. "Protein turnover—what does it mean for animal production?" Canadian Journal of Animal Science 83, no. 3 (September 1, 2003): 327–40. http://dx.doi.org/10.4141/a03-019.

Full text

Abstract:

The dynamics of protein turnover confer great advantages for homeothermy, plasticity and metabolic function in mammals. The different roles played by the various organs have led to aspects of protein synthesis and degradation that aid the various functions performed. The so-called “non-productive” organs such as the gastro-intestinal tract and liver produce large quantities of export proteins that perform vital functions. Not all these proteins are recovered, however, and thus function can result in lowered net conversion of plant protein to animal products. The splanchnic tissues also oxidize essential amino acids (AA). For example, the gut catabolizes leucine, lysine and methionine, but not threonine and phenylalanine, as part of a complex interaction between AA supply and tissue metabolic activity. Losses by oxidation and endogenous secretions can markedly alter the pattern of absorbed AA. The fractional rates of extraction of total AA inflow to the liver are low and this allows short-term flexibility in controlling supply to peripheral tissues. Recent evidence suggests that the role of the liver in AA catabolism is more a response to non-use by other tissues rather than an immediate regulation of supply to the periphery. Neither arterial supply of AA nor the rate of transport into peripheral tissues limits protein gain, except when supply is very limited. Rather, control is probably exerted via hormone-nutrient interactions. Key words: Protein synthesis, amino acid, gastro-intestinal tract, liver, muscle, mammary gland

APA, Harvard, Vancouver, ISO, and other styles

7

Liu, Yingying, Fengna Li, Lingyun He, Bie Tan, Jinping Deng, Xiangfeng Kong, Yinghui Li, Meimei Geng, Yulong Yin, and Guoyao Wu. "Dietary protein intake affects expression of genes for lipid metabolism in porcine skeletal muscle in a genotype-dependent manner." British Journal of Nutrition 113, no. 7 (March 16, 2015): 1069–77. http://dx.doi.org/10.1017/s0007114514004310.

Full text

Abstract:

Skeletal muscle is a major site for the oxidation of fatty acids (FA) in mammals, including humans. Using a swine model, we tested the hypothesis that dietary protein intake regulates the expression of key genes for lipid metabolism in skeletal muscle. A total of ninety-six barrows (forty-eight pure-bred Bama mini-pigs (fatty genotype) and forty-eight Landrace pigs (lean genotype)) were fed from 5 weeks of age to market weight. Pigs of fatty or lean genotype were randomly assigned to one of two dietary treatments (low- or adequate-protein diet), with twenty-four individually fed pigs per treatment. Our data showed that dietary protein levels affected the expression of genes involved in the anabolism and catabolism of lipids in the longissimus dorsi and biceps femoris muscles in a genotype-dependent manner. Specifically, Bama mini-pigs had more intramuscular fat, SFA and MUFA, as well as elevated mRNA expression levels of lipogenic genes, compared with Landrace pigs. In contrast, Bama mini-pigs had lower mRNA expression levels of lipolytic genes than Landrace pigs fed an adequate-protein diet in the growing phase. These data are consistent with higher white-fat deposition in Bama mini-pigs than in Landrace pigs. In conclusion, adequate provision of dietary protein (amino acids) plays an important role in regulating the expression of key lipogenic genes, and the growth of white adipose tissue, in a genotype- and tissue-specific manner. These findings have important implications for developing novel dietary strategies in pig production.

APA, Harvard, Vancouver, ISO, and other styles

8

MacIver, Bryce, Craig P. Smith, Warren G. Hill, and Mark L. Zeidel. "Functional characterization of mouse urea transporters UT-A2 and UT-A3 expressed in purified Xenopus laevis oocyte plasma membranes." American Journal of Physiology-Renal Physiology 294, no. 4 (April 2008): F956—F964. http://dx.doi.org/10.1152/ajprenal.00229.2007.

Full text

Abstract:

Urea is a small solute synthesized by many terrestrial organisms as part of the catabolism of protein. In mammals it is transported across cellular membranes by specific urea transporter (UT) proteins that are the products of two separate, but closely related genes, referred to as UT-A and UT-B. Three major UT-A isoforms are found in the kidney, namely UT-A1, UT-A2, and UT-A3. UT-A2 is found in the thin, descending limb of the loop of Henle, whereas UT-A1 and UT-A3 are concentrated in the inner medullary collecting duct. UT-A2 and UT-A3 effectively represent two halves of the whole UT-A gene and, when joined together by 73 hydrophilic amino acids, constitute UT-A1. A biophysical characterization of mouse UT-A2 and UT-A3 was undertaken by expression in Xenopus laevis oocytes and subsequent preparation of highly enriched plasma membrane vesicles for use in stopped-flow fluorometry. Both isoforms were found to be highly specific for urea, and did not permeate water, ammonia, or other molecules closely related to urea (formamide, acetamide, methylurea, and dimethylurea). Single transporter flux rates of 46,000 ± 10,000 and 59,000 ± 15,000 (means ± SE) urea molecules/s/channel for UT-A2 and UT-A3, respectively, were obtained. Overall, the UT-A2 and UT-A3 isoforms appear to have identical functional kinetics.

APA, Harvard, Vancouver, ISO, and other styles

9

Wallace, R. John. "Catabolism of Amino Acids by Megasphaera elsdenii LC1." Applied and Environmental Microbiology 51, no. 5 (1986): 1141–43. http://dx.doi.org/10.1128/aem.51.5.1141-1143.1986.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Neinast, Michael, Danielle Murashige, and Zoltan Arany. "Branched Chain Amino Acids." Annual Review of Physiology 81, no. 1 (February 10, 2019): 139–64. http://dx.doi.org/10.1146/annurev-physiol-020518-114455.

Full text

Abstract:

Branched chain amino acids (BCAAs) are building blocks for all life-forms. We review here the fundamentals of BCAA metabolism in mammalian physiology. Decades of studies have elicited a deep understanding of biochemical reactions involved in BCAA catabolism. In addition, BCAAs and various catabolic products act as signaling molecules, activating programs ranging from protein synthesis to insulin secretion. How these processes are integrated at an organismal level is less clear. Inborn errors of metabolism highlight the importance of organismal regulation of BCAA physiology. More recently, subtle alterations of BCAA metabolism have been suggested to contribute to numerous prevalent diseases, including diabetes, cancer, and heart failure. Understanding the mechanisms underlying altered BCAA metabolism and how they contribute to disease pathophysiology will keep researchers busy for the foreseeable future.

APA, Harvard, Vancouver, ISO, and other styles

11

Bender, David A. "The metabolism of “surplus” amino acids." British Journal of Nutrition 108, S2 (August 2012): S113—S121. http://dx.doi.org/10.1017/s0007114512002292.

Full text

Abstract:

For an adult in N balance, apart from small amounts of amino acids required for the synthesis of neurotransmitters, hormones, etc, an amount of amino acids almost equal to that absorbed from the diet can be considered to be “surplus” in that it will be catabolized. The higher diet-induced thermogenesis from protein than from carbohydrate or fat has generally been assumed to be due to increased protein synthesis, which is ATP expensive. To this must be added the ATP cost of protein catabolism through the ubiquitin-proteasome pathway. Amino acid catabolism will add to thermogenesis. Deamination results in net ATP formation except when serine and threonine deaminases are used, but there is the energy cost of synthesizing glutamine in extra-hepatic tissues. The synthesis of urea has a net cost of only 1·5 × ATP when the ATP yield from fumarate metabolism is offset against the ATP cost of the urea cycle, but this offset is thermogenic. In fasting and on a low carbohydrate diet as much of the amino acid carbon as possible will be used for gluconeogenesis – an ATP-expensive, and hence thermogenic, process. Complete oxidation of most amino acid carbon skeletons also involves a number of thermogenic steps in which ATP (or GTP) or reduced coenzymes are utilized. There are no such thermogenic steps in the metabolism of pyruvate, acetyl CoA or acetoacetate, but for amino acids that are metabolized by way of the citric acid cycle intermediates there is thermogenesis ranging from 1 up to 7 × ATP equivalent per mol.

APA, Harvard, Vancouver, ISO, and other styles

12

Chen, Lixiang, Peng Li, Junjun Wang, Xilong Li, Haijun Gao, Yulong Yin, Yongqing Hou, and Guoyao Wu. "Catabolism of nutritionally essential amino acids in developing porcine enterocytes." Amino Acids 37, no. 1 (March 17, 2009): 143–52. http://dx.doi.org/10.1007/s00726-009-0268-1.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

de Castro Ghizoni, Cristiane Vizioli, Fabiana Rodrigues Silva Gasparin, Antonio Sueiti Maeda Júnior, Fernando Olinto Carreño, Rodrigo Polimeni Constantin, Adelar Bracht, Emy Luiza Ishii Iwamoto, and Jorgete Constantin. "Catabolism of amino acids in livers from cafeteria-fed rats." Molecular and Cellular Biochemistry 373, no. 1-2 (November 2, 2012): 265–77. http://dx.doi.org/10.1007/s11010-012-1499-0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Zhang, Meng, Yuting Fu, Yuhao Chen, Yuze Ma, Zhixin Guo, Yanfeng Wang, Huifang Hao, Quan Fu, and Zhigang Wang. "Inhibition of the mTORC1/NF-κB Axis Alters Amino Acid Metabolism in Human Hepatocytes." BioMed Research International 2021 (January 18, 2021): 1–15. http://dx.doi.org/10.1155/2021/8621464.

Full text

Abstract:

In addition to serving as the building blocks for protein synthesis, amino acids can be used as an energy source, through catabolism. The transamination, oxidative deamination, and decarboxylation processes that occur during amino acid catabolism are catalyzed by specific enzymes, including aspartate aminotransferase (AST), glutamate dehydrogenase (GDH), glutamic acid decarboxylase (GAD), and ornithine decarboxylase (ODC); however, the overall molecular mechanisms through which amino acid catabolism occurs remain largely unknown. To examine the role of mechanistic target of rapamycin complex 1 (mTORC1) on amino acid catabolism, mTORC1 was inactivated by rapamycin or shRNA targeting Raptor, versus activated by overexpressing Rheb or amino acids in human hepatocytes. The expression of amino acid catabolic genes and related transcription factor was investigated by RT/real-time PCR and western blot analysis. A few types of amino acid metabolite were examined by ELISA and HPLC analysis. The data showed that inactivated mTORC1 resulted in inhibition of NF-κB and the expression of AST, GDH, GAD, and ODC, whereas activated mTORC1 enhanced NF-κB activation and the expression levels of the catabolism-associated genes. Further, inhibition of NF-κB reduced the expression levels of AST, GDH, GAD, and ODC. mTORC1 upregulated NF-κB activation and the expression of AST and ODC in response to glutamate and ornithine treatments, whereas rapamycin inhibited the utilization of glutamate and ornithine in hepatocytes. Taken together, these results indicated that the mTORC1/NF-κB axis modulates the rate of amino acid catabolism by regulating the expression of key catabolic enzymes in hepatocytes.

APA, Harvard, Vancouver, ISO, and other styles

15

Raj, Dominic S. C., Oladipo Adeniyi, Elizabeth A. Dominic, Michel A. Boivin, Sandra McClelland, Antonios H. Tzamaloukas, Nancy Morgan, Lawrence Gonzales, Robert Wolfe, and Arny Ferrando. "Amino acid repletion does not decrease muscle protein catabolism during hemodialysis." American Journal of Physiology-Endocrinology and Metabolism 292, no. 6 (June 2007): E1534—E1542. http://dx.doi.org/10.1152/ajpendo.00599.2006.

Full text

Abstract:

Intradialytic protein catabolism is attributed to loss of amino acids in the dialysate. We investigated the effect of amino acid infusion during hemodialysis (HD) on muscle protein turnover and amino acid transport kinetics by using stable isotopes of phenylalanine, leucine, and lysine in eight patients with end-stage renal disease (ESRD). Subjects were studied at baseline (pre-HD), 2 h of HD without amino acid infusion (HD-O), and 2 h of HD with amino acid infusion (HD+AA). Amino acid depletion during HD-O augmented the outward transport of amino acids from muscle into the vein. Increased delivery of amino acids to the leg during HD+AA facilitated the transport of amino acids from the artery into the intracellular compartment. Increase in muscle protein breakdown was more than the increase in synthesis during HD-O (46.7 vs. 22.3%, P < 0.001). Net balance (nmol·min−1·100 ml −1) was more negative during HD-O compared with pre-HD (−33.7 ± 1.5 vs. −6.0 ± 2.3, P < 0.001). Despite an abundant supply of amino acids, the net balance (−16.9 ± 1.8) did not switch from net release to net uptake. HD+AA induced a proportional increase in muscle protein synthesis and catabolism. Branched chain amino acid catabolism increased significantly from baseline during HD-O and did not decrease during HD+AA. Protein synthesis efficiency, the fraction of amino acid in the intracellular pool that is utilized for muscle protein synthesis decreased from 42.1% pre-HD to 33.7 and 32.6% during HD-O and HD+AA, respectively ( P < 0.01). Thus amino acid repletion during HD increased muscle protein synthesis but did not decrease muscle protein breakdown.

APA, Harvard, Vancouver, ISO, and other styles

16

Langenbuch, M., and H. O. Pörtner. "Changes in metabolic rate and N excretion in the marine invertebrateSipunculus nudusunder conditions of environmental hypercapnia." Journal of Experimental Biology 205, no. 8 (April 15, 2002): 1153–60. http://dx.doi.org/10.1242/jeb.205.8.1153.

Full text

Abstract:

SUMMARYIncreased CO2 partial pressures (hypercapnia) as well as hypoxia are natural features of marine environments like the intertidal zone. Nevertheless little is known about the specific effects of CO2 on metabolism, except for the well-described effects on acid—base variables and regulation. Accordingly, the sediment-dwelling worm Sipunculus nudus was used as an experimental model to investigate the correlation of acid—base-induced metabolic depression and protein/amino acid catabolism, by determining the rates of oxygen consumption, ammonia excretion and O/N ratios in non-perfused preparations of body wall musculature at various levels of extra- and intracellular pH, PCO2 and [HCO3-]. A decrease in extracellular pH from control level (7.9) to 6.7 caused a reduction in aerobic metabolic rate of both normocapnic and hypercapnic tissues by 40-45 %. O/N ratios of 4.0-4.5 under control conditions indicate that amino acid catabolism meets the largest fraction of aerobic energy demand. A significant 10-15 % drop in ammonia excretion, a simultaneous reduction of O/N ratios and a transient accumulation of intracellular bicarbonate during transition to extreme acidosis suggest a reduction in net amino acid catabolism and a shift in the selection of amino acids used,favouring monoamino dicarboxylic acids and their amines (asparagine,glutamine, aspartic and glutamic acids). A drop in intracellular pH was identified as mediating this effect. In conclusion, the present data provide evidence for a regulatory role of intracellular pH in the selection of amino acids used by catabolism.

APA, Harvard, Vancouver, ISO, and other styles

17

Mansour, S., J. M. Beckerich, and P. Bonnarme. "Lactate and Amino Acid Catabolism in the Cheese-Ripening Yeast Yarrowia lipolytica." Applied and Environmental Microbiology 74, no. 21 (September 5, 2008): 6505–12. http://dx.doi.org/10.1128/aem.01519-08.

Full text

Abstract:

ABSTRACT The consumption of lactate and amino acids is very important for microbial development and/or aroma production during cheese ripening. A strain of Yarrowia lipolytica isolated from cheese was grown in a liquid medium containing lactate in the presence of a low (0.1ï¿½) or high (2ï¿½) concentration of amino acids. Our results show that there was a dramatic increase in the growth of Y. lipolytica in the medium containing a high amino acid concentration, but there was limited lactate consumption. Conversely, lactate was efficiently consumed in the medium containing a low concentration of amino acids after amino acid depletion was complete. These data suggest that the amino acids are used by Y. lipolytica as a main energy source, whereas lactate is consumed following amino acid depletion. Amino acid degradation was accompanied by ammonia production corresponding to a dramatic increase in the pH. The effect of adding amino acids to a Y. lipolytica culture grown on lactate was also investigated. Real-time quantitative PCR analyses were performed with specific primers for five genes involved in amino acid transport and catabolism, including an amino acid transporter gene (GAP1) and four aminotransferase genes (ARO8, ARO9, BAT1, and BAT2). The expression of three genes involved in lactate transport and catabolism was also studied. These genes included a lactate transporter gene (JEN1) and two lactate dehydrogenase genes (CYB2-1 and CYB2-2). Our data showed that GAP1, BAT2, BAT1, and ARO8 were maximally expressed after 15 to 30 min following addition of amino acids (BAT2 was the most highly expressed gene), while the maximum expression of JEN1, CYB2-1, and CYB2-2 was delayed (≥60 min).

APA, Harvard, Vancouver, ISO, and other styles

18

Wang, Jian, Chenyi Li, Yusong Zou, and Yajun Yan. "Bacterial synthesis of C3-C5 diols via extending amino acid catabolism." Proceedings of the National Academy of Sciences 117, no. 32 (July 27, 2020): 19159–67. http://dx.doi.org/10.1073/pnas.2003032117.

Full text

Abstract:

Amino acids are naturally occurring and structurally diverse metabolites in biological system, whose potentials for chemical expansion, however, have not been fully explored. Here, we devise a metabolic platform capable of producing industrially important C3-C5 diols from amino acids. The presented platform combines the natural catabolism of charged amino acids with a catalytically efficient and thermodynamically favorable diol formation pathway, created by expanding the substrate scope of the carboxylic acid reductase toward noncognate ω-hydroxylic acids. Using the established platform as gateways, seven different diol-convertible amino acids are converted to diols including 1,3-propanediol, 1,4-butanediol, and 1,5-pentanediol. Particularly, we afford to optimize the production of 1,4-butanediol and demonstrate the de novo production of 1,5-pentanediol from glucose, with titers reaching 1.41 and 0.97 g l−1, respectively. Our work presents a metabolic platform that enriches the pathway repertoire for nonnatural diols with feedstock flexibility to both sugar and protein hydrolysates.

APA, Harvard, Vancouver, ISO, and other styles

19

Iraqui, Ismaïl, Stéphan Vissers, Bruno André, and Antonio Urrestarazu. "Transcriptional Induction by Aromatic Amino Acids in Saccharomyces cerevisiae." Molecular and Cellular Biology 19, no. 5 (May 1, 1999): 3360–71. http://dx.doi.org/10.1128/mcb.19.5.3360.

Full text

Abstract:

ABSTRACT Aromatic aminotransferase II, product of the ARO9 gene, catalyzes the first step of tryptophan, phenylalanine, and tyrosine catabolism in Saccharomyces cerevisiae. ARO9 expression is under the dual control of specific induction and nitrogen source regulation. We have here identified UASaro, a 36-bp upstream element necessary and sufficient to promote transcriptional induction of reporter gene expression in response to tryptophan, phenylalanine, or tyrosine. We then isolated mutants in which UASaro-mediated ARO9 transcription is partially or totally impaired. Mutations abolishingARO9 induction affect a gene called ARO80(YDR421w), coding for a Zn2Cys6 family transcription factor. A sequence highly similar to UASaro was found upstream from theYDR380w gene encoding a homolog of bacterial indolepyruvate decarboxylase. In yeast, this enzyme is postulated to catalyze the second step of tryptophan catabolism to tryptophol. We show that ARO9 and YDR380w(named ARO10) have similar patterns of transcriptional regulation and are both under the positive control of Aro80p. Nitrogen regulation of ARO9 expression seems not directly to involve the general factor Ure2p, Gln3p, Nil1p, Uga43p, or Gzf3p.ARO9 expression appears, rather, to be mainly regulated by inducer exclusion. Finally, we show that Gap1p, the general amino acid permease, and Wap1p (Ycl025p), a newly discovered inducible amino acid permease with broad specificity, are the main aromatic amino acid transporters for catabolic purposes.

APA, Harvard, Vancouver, ISO, and other styles

20

O'Sullivan, Dan, John T. Brosnan, and Margaret E. Brosnan. "Catabolism of arginine and ornithine in the perfused rat liver: effect of dietary protein and of glucagon." American Journal of Physiology-Endocrinology and Metabolism 278, no. 3 (March 1, 2000): E516—E521. http://dx.doi.org/10.1152/ajpendo.2000.278.3.e516.

Full text

Abstract:

The rates of oxidation of arginine and ornithine that occurred through a reaction pathway involving the enzyme ornithine aminotransferase (EC 2.6.1.13 ) were determined using14C-labeled amino acids in the isolated nonrecirculating perfused rat liver. At physiological concentrations of these amino acids, their catabolism is subject to chronic regulation by the level of protein consumed in the diet. 14CO2production from [U-14C]ornithine (0.1 mM) and from [U-14C]arginine (0.2 mM) was increased about fourfold in livers from rats fed 60% casein diets for 3–4 days. The catabolism of arginine in the perfused rat liver, but not that of ornithine, is subject to acute regulation by glucagon (10− 7 M), which stimulated arginine catabolism by ∼40%. Dibutyryl cAMP (0.1 mM) activated arginine catabolism to a similar extent. In retrograde perfusions, glucagon caused a twofold increase in the rate of arginine catabolism, suggesting an effect of glucagon on arginase in the perivenous cells.

APA, Harvard, Vancouver, ISO, and other styles

21

Bifari, Francesco, and Enzo Nisoli. "Branched-chain amino acids differently modulate catabolic and anabolic states in mammals: a pharmacological point of view." British Journal of Pharmacology 174, no. 11 (October 25, 2016): 1366–77. http://dx.doi.org/10.1111/bph.13624.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Nagata, Y., R. Konno, Y. Yasumura, and T. Akino. "Involvement of d-amino acid oxidase in elimination of free d-amino acids in mice." Biochemical Journal 257, no. 1 (January 1, 1989): 291–92. http://dx.doi.org/10.1042/bj2570291.

Full text

Abstract:

The physiological role of D-amino acid oxidase was investigated by using mutant ddY/DAO- mice lacking the enzyme. Free D-amino acid concentrations in the mutant mice were significantly higher than those of control ddY/DAO+ mice in kidney, liver, lung, heart, brain, erythrocytes, serum and urine. The results suggest that the enzyme is involved in the catabolism of free D-amino acids in the body, and that free D-amino acids are also excreted into urine.

APA, Harvard, Vancouver, ISO, and other styles

23

Yue, Shi-Jun, Juan Liu, Ai-Ting Wang, Xin-Tong Meng, Zhi-Rui Yang, Cheng Peng, Hua-Shi Guan, Chang-Yun Wang, and Dan Yan. "Berberine alleviates insulin resistance by reducing peripheral branched-chain amino acids." American Journal of Physiology-Endocrinology and Metabolism 316, no. 1 (January 1, 2019): E73—E85. http://dx.doi.org/10.1152/ajpendo.00256.2018.

Full text

Abstract:

Increased circulating branched-chain amino acids (BCAAs) have been involved in the pathogenesis of obesity and insulin resistance (IR). However, evidence relating berberine (BBR), gut microbiota, BCAAs, and IR is limited. Here, we showed that BBR could effectively rectify steatohepatitis and glucose intolerance in high-fat diet (HFD)-fed mice. BBR reorganized gut microbiota populations under both the normal chow diet (NCD) and HFD. Particularly, BBR noticeably decreased the relative abundance of BCAA-producing bacteria, including order Clostridiales; families Streptococcaceae, Clostridiaceae, and Prevotellaceae; and genera Streptococcus and Prevotella. Compared with the HFD group, predictive metagenomics indicated a reduction in the proportion of gut microbiota genes involved in BCAA biosynthesis but the enrichment genes for BCAA degradation and transport by BBR treatment. Accordingly, the elevated serum BCAAs of HFD group were significantly decreased by BBR. Furthermore, the Western blotting results implied that BBR could promote the BCAA catabolism in the liver and epididymal white adipose tissues of HFD-fed mice by activation of the multienzyme branched-chain α-ketoacid dehydrogenase complex (BCKDC), whereas by inhibition of the phosphorylation state of BCKDHA (E1α subunit) and branched-chain α-ketoacid dehydrogenase kinase (BCKDK). The ex vivo assay further confirmed that BBR could increase BCAA catabolism in both AML12 hepatocytes and 3T3-L1 adipocytes. Finally, data from healthy subjects and diabetics confirmed that BBR could improve glycemic control and modulate circulating BCAAs. Together, our findings clarified BBR improving IR associated not only with gut microbiota alteration in BCAA biosynthesis but also with BCAA catabolism in liver and adipose tissues.

APA, Harvard, Vancouver, ISO, and other styles

24

Lee, S. H. C., and E. J. Davis. "Amino acid catabolism by perfused rat hindquarter. The metabolic fates of valine." Biochemical Journal 233, no. 3 (February 1, 1986): 621–30. http://dx.doi.org/10.1042/bj2330621.

Full text

Abstract:

Hindquarters from starved rats were perfused with plasma concentrations of amino acids, but without other added substrates. Release of amino acids was similar to that previously reported, but, if total amino acid changes were recorded, alanine and glutamine were not formed in excess of their occurrence in muscle proteins. In protein balance (excess insulin) there was no net formation of either alanine or glutamine, even though the branched-chain amino acids and methionine were consumed. If [U-14C]valine was present, radiolabelled 3-hydroxyisobutyrate and, to a lesser extent, 2-oxo-3-methylbutyrate accumulated and radiolabel was incorporated into citrate-cycle intermediates and metabolites closely associated with the citrate cycle (glutamine and glutamate, and, to a smaller extent, lactate and alanine). If a 2-chloro-4-methylvalerate was present to stimulate the branched-chain oxo acid dehydrogenase, flux through this step was accelerated, resulting in increased accumulation of 3-hydroxyisobutyrate, decreased accumulation of 2-oxo-3-methylbutyrate, and markedly increased incorporation of radiolabel (specific and total) into all measured metabolites formed after 3-hydroxyisobutyrate. It is concluded that: amino acid catabolism by skeletal muscle is confined to degradation of the branched-chain amino acids, methionine and those that are interconvertible with the citrate cycle; amino acid catabolism is relatively minor in supplying carbon for net synthesis of alanine and glutamine; and partial degradation products of the branched-chain amino acids are quantitatively significant substrates released from muscle for hepatic gluconeogenesis. For valine, 3-hydroxyisobutyrate appears to be quantitatively the most important intermediate released from muscle. A side path for inter-organ disposition of the branched-chain amino acids is proposed.

APA, Harvard, Vancouver, ISO, and other styles

25

Ballatori, N., R. Jacob, C. Barrett, and J. L. Boyer. "Biliary catabolism of glutathione and differential reabsorption of its amino acid constituents." American Journal of Physiology-Gastrointestinal and Liver Physiology 254, no. 1 (January 1, 1988): G1—G7. http://dx.doi.org/10.1152/ajpgi.1988.254.1.g1.

Full text

Abstract:

Biliary excretion of glutathione, free amino acids, and total amino acids (after acid hydrolysis) was measured in hepatic bile collected from guinea pigs, rabbits, and dogs anesthetized with pentobarbital sodium. In controls, the concentration of glutathione in bile was less than 20 microM in all three species. However, when hepatic gamma-glutamyltransferase activity was decreased by retrograde intrabiliary infusion of the irreversible inhibitor acivicin (AT-125; 20 mumol/kg), there was a marked increase in biliary glutathione excretion (in mumol glutathione equivalents.kg body wt-1.h-1) from 0.10 +/- 0.04 to 2.2 +/- 0.6 in guinea pigs, from 0.014 +/- 0.013 to 2.5 +/- 1.9 in rabbits, and from an undetectable level (less than 0.001) to 0.11 +/- 0.05 in dogs. Amino acid analysis of bile revealed that the concentration of glutathione's constituent amino acids (free glutamate, cystine, and glycine) in control bile samples from these three species were quite low and were not affected by AT-125. However, acid hydrolyzates of these same bile samples revealed an unusually high degree of amino acid conjugation. Glutamate (0.06-0.5 mM), cystine (0.2-1.1 mM), and glycine (1.7-2.8 mM) constituted the overwhelming majority of total amino acids in hydrolyzed bile from controls. After AT-125, concentrations of total glutamate and cystine were elevated in hydrolyzed bile, while concentrations of all other amino acids remained the same. Thus glutathione is avidly secreted into bile in the guinea pig, rabbit, and dog but is almost quantitatively broken down within the biliary tree. Subsequently, the glutamate and cysteine moieties derived from catabolism of glutathione must be partially reabsorbed either as peptides, conjugates, or free amino acids.(ABSTRACT TRUNCATED AT 250 WORDS)

APA, Harvard, Vancouver, ISO, and other styles

26

Raj, Dominic S. C., Philip Zager, Vallbh O. Shah, Elizabeth A. Dominic, Oladipo Adeniyi, Pedro Blandon, Robert Wolfe, and Arny Ferrando. "Protein turnover and amino acid transport kinetics in end-stage renal disease." American Journal of Physiology-Endocrinology and Metabolism 286, no. 1 (January 2004): E136—E143. http://dx.doi.org/10.1152/ajpendo.00352.2003.

Full text

Abstract:

Protein and amino acid metabolism is abnormal in end-stage renal disease (ESRD). Protein turnover is influenced by transmembrane amino acid transport. The effect of ESRD and hemodialysis (HD) on intracellular amino acid transport kinetics is unknown. We studied intracellular amino acid transport kinetics and protein turnover by use of stable isotopes of phenylalanine, leucine, lysine, alanine, and glutamine before and during HD in six ESRD patients. Data obtained from amino acid concentrations and enrichment in the artery, vein, and muscle compartments were used to calculate intracellular amino acid transport and muscle protein synthesis and catabolism. Fractional muscle protein synthesis (FSR) was estimated by the precursor product approach. Despite a significant decrease in the plasma concentrations of amino acids in the artery and vein during HD, the intracellular concentrations remained stable. Outward transport of the amino acids was significantly higher than the inward transport during HD. FSR increased during HD (0.0521 ± 0.0043 vs. 0.0772 ± 0.0055%/h, P < 0.01). Results derived from compartmental modeling indicated that both protein synthesis (118.3 ± 20.6 vs. 146.5 ± 20.6 nmol·min-1·100 ml leg-1, P < 0.01) and catabolism (119.8 ± 18.0 vs. 174.0 ± 14.2 nmol·min-1·100 ml leg-1, P < 0.01) increased during HD. However, the intradialytic increase in catabolism exceeded that of synthesis (57.8 ± 13.8 vs. 28.0 ± 8.5%, P < 0.05). Thus HD alters amino acid transport kinetics and increases protein turnover, with net increase in protein catabolism.

APA, Harvard, Vancouver, ISO, and other styles

27

Poindexter, B. B., C. A. Karn, J. A. Ahlrichs, J. Wang, C. A. Leitch, E. A. Liechty, and S. C. Denne. "Amino acids suppress proteolysis independent of insulin throughout the neonatal period." American Journal of Physiology-Endocrinology and Metabolism 272, no. 4 (April 1, 1997): E592—E599. http://dx.doi.org/10.1152/ajpendo.1997.272.4.e592.

Full text

Abstract:

To determine how increased amino acid availability alters rates of whole body proteolysis and the irreversible catabolism of the essential amino acids leucine and phenylalanine throughout the neonatal period, leucine and phenylalanine kinetics were measured under basal conditions and in response to intravenous amino acids in two separate groups of healthy, full-term newborns (at 3 days and 3 wk of age). The endogenous rates of appearance of leucine and phenylalanine (reflecting proteolysis) were suppressed equally in both groups and in a dose-dependent fashion (by approximately 10% with 1.2 g x kg(-1) x day(-1) and by approximately 20% with 2.4 g x kg(-1) x day(-1)) in response to intravenous amino acid delivery. Insulin concentrations remained unchanged from basal values during amino acid administration. The irreversible catabolism of leucine and phenylalanine increased in a stepwise fashion in response to intravenous amino acids; again, no differences were observed between the two groups. This study clearly demonstrates that the capacity to acutely increase rates of leucine oxidation and phenylalanine hydroxylation is fully present early in the neonatal period in normal newborns. Furthermore, these data suggest that amino acid availability is a primary regulator of proteolysis in normal newborns throughout the neonatal period.

APA, Harvard, Vancouver, ISO, and other styles

28

Caing-Carlsson, Rhawnie, Parveen Goyal, Amit Sharma, Swagatha Ghosh, Thanuja Gangi Setty, Rachel A. North, Rosmarie Friemann, and S. Ramaswamy. "Crystal structure ofN-acetylmannosamine kinase fromFusobacterium nucleatum." Acta Crystallographica Section F Structural Biology Communications 73, no. 6 (May 31, 2017): 356–62. http://dx.doi.org/10.1107/s2053230x17007439.

Full text

Abstract:

Sialic acids comprise a varied group of nine-carbon amino sugars that are widely distributed among mammals and higher metazoans. Some human commensals and bacterial pathogens can scavenge sialic acids from their environment and degrade them for use as a carbon and nitrogen source. The enzymeN-acetylmannosamine kinase (NanK; EC 2.7.1.60) belongs to the transcriptional repressors, uncharacterized open reading frames and sugar kinases (ROK) superfamily. NanK catalyzes the second step of the sialic acid catabolic pathway, transferring a phosphate group from adenosine 5′-triphosphate to the C6 position ofN-acetylmannosamine to generateN-acetylmannosamine 6-phosphate. The structure of NanK fromFusobacterium nucleatumwas determined to 2.23 Å resolution by X-ray crystallography. Unlike other NanK enzymes and ROK family members,F. nucleatumNanK does not have a conserved zinc-binding site. In spite of the absence of the zinc-binding site, all of the major structural features of enzymatic activity are conserved.

APA, Harvard, Vancouver, ISO, and other styles

29

Griffin, Jeddidiah W. D., and Patrick C. Bradshaw. "Amino Acid Catabolism in Alzheimer’s Disease Brain: Friend or Foe?" Oxidative Medicine and Cellular Longevity 2017 (2017): 1–15. http://dx.doi.org/10.1155/2017/5472792.

Full text

Abstract:

There is a dire need to discover new targets for Alzheimer’s disease (AD) drug development. Decreased neuronal glucose metabolism that occurs in AD brain could play a central role in disease progression. Little is known about the compensatory neuronal changes that occur to attempt to maintain energy homeostasis. In this review using the PubMed literature database, we summarize evidence that amino acid oxidation can temporarily compensate for the decreased glucose metabolism, but eventually altered amino acid and amino acid catabolite levels likely lead to toxicities contributing to AD progression. Because amino acids are involved in so many cellular metabolic and signaling pathways, the effects of altered amino acid metabolism in AD brain are far-reaching. Possible pathological results from changes in the levels of several important amino acids are discussed. Urea cycle function may be induced in endothelial cells of AD patient brains, possibly to remove excess ammonia produced from increased amino acid catabolism. Studying AD from a metabolic perspective provides new insights into AD pathogenesis and may lead to the discovery of dietary metabolite supplements that can partially compensate for alterations of enzymatic function to delay AD or alleviate some of the suffering caused by the disease.

APA, Harvard, Vancouver, ISO, and other styles

30

Grantham, Barbara D., and J. Barrett. "Amino acid catabolism in the nematodes Heligmosomoides polygyrus and Panagrellus redivivus 2. Metabolism of the carbon skeleton." Parasitology 93, no. 3 (December 1986): 495–504. http://dx.doi.org/10.1017/s0031182000081208.

Full text

Abstract:

SUMMARYAll of the enzymes of proline catabolism were present in Heligmosomoides polygyrus and Panagrellus redivivus and the activities were, in general, similar to those found in rat liver. Both nematodes were also shown to be able to catabolize the branched-chain amino acids leucine, isoleucine and valine, by pathways similar to those found in mammalian liver. There were no significant differences in amino acid catabolism between the animal-parasitic and free-living species of nematode.

APA, Harvard, Vancouver, ISO, and other styles

31

Dalal, Seema, and Michael Klemba. "Roles for Two Aminopeptidases in Vacuolar Hemoglobin Catabolism in Plasmodium falciparum." Journal of Biological Chemistry 282, no. 49 (September 25, 2007): 35978–87. http://dx.doi.org/10.1074/jbc.m703643200.

Full text

Abstract:

During the erythrocytic stage of its life cycle, the human malaria parasite Plasmodium falciparum catabolizes large quantities of host-cell hemoglobin in an acidic organelle, the food vacuole. A current model for the catabolism of globin-derived oligopeptides invokes peptide transport out of the food vacuole followed by hydrolysis to amino acids by cytosolic aminopeptidases. To test this model, we have examined the roles of four parasite aminopeptidases during the erythrocytic cycle. Localization of tagged aminopeptidases, coupled with biochemical analysis of enriched food vacuoles, revealed the presence of amino acid-generating pathways in the food vacuole as well as the cytosol. Based on the localization data and in vitro assays, we propose a specific role for one of the plasmodial enzymes, aminopeptidase P, in the catabolism of proline-containing peptides in both the vacuole and the cytosol. We establish an apparent requirement for three of the four aminopeptidases (including the two food vacuole enzymes) for efficient parasite proliferation. To gain insight into the impact of aminopeptidase inhibition on parasite development, we examined the effect of the presence of amino acids in the culture medium of the parasite on the toxicity of the aminopeptidase inhibitor bestatin. The ability of bestatin to block parasite replication was only slightly affected when 19 of 20 amino acids were withdrawn from the medium, indicating that exogenous amino acids cannot compensate for the loss of aminopeptidase activity. Together, these results support the development of aminopeptidase inhibitors as novel chemotherapeutics directed against malaria.

APA, Harvard, Vancouver, ISO, and other styles

32

Williams, A. G., J. Noble, and J. M. Banks. "Catabolism of amino acids by lactic acid bacteria isolated from Cheddar cheese." International Dairy Journal 11, no. 4-7 (July 2001): 203–15. http://dx.doi.org/10.1016/s0958-6946(01)00050-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Illsinger, S., T. L�cke, U. Meyer, B. Vaske, and A. M. Das. "Branched chain amino acids as a parameter for catabolism in treated phenylketonuria." Amino Acids 28, no. 1 (December 22, 2004): 45–50. http://dx.doi.org/10.1007/s00726-004-0150-0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Kieronczyk, Agnieszka, Siv Skeie, Thor Langsrud, and Mireille Yvon. "Cooperation between Lactococcus lactis and Nonstarter Lactobacilli in the Formation of Cheese Aroma from Amino Acids." Applied and Environmental Microbiology 69, no. 2 (February 2003): 734–39. http://dx.doi.org/10.1128/aem.69.2.734-739.2003.

Full text

Abstract:

ABSTRACT In Gouda and Cheddar type cheeses the amino acid conversion to aroma compounds, which is a major process for aroma formation, is essentially due to lactic acid bacteria (LAB). In order to evaluate the respective role of starter and nonstarter LAB and their interactions in cheese flavor formation, we compared the catabolism of phenylalanine, leucine, and methionine by single strains and strain mixtures of Lactococcus lactis subsp. cremoris NCDO763 and three mesophilic lactobacilli. Amino acid catabolism was studied in vitro at pH 5.5, by using radiolabeled amino acids as tracers. In the presence of α-ketoglutarate, which is essential for amino acid transamination, the lactobacillus strains degraded less amino acids than L. lactis subsp. cremoris NCDO763, and produced mainly nonaromatic metabolites. L. lactis subsp. cremoris NCDO763 produced mainly the carboxylic acids, which are important compounds for cheese aroma. However, in the reaction mixture containing glutamate, only two lactobacillus strains degraded amino acids significantly. This was due to their glutamate dehydrogenase (GDH) activity, which produced α-ketoglutarate from glutamate. The combination of each of the GDH-positive lactobacilli with L. lactis subsp. cremoris NCDO763 had a beneficial effect on the aroma formation. Lactobacilli initiated the conversion of amino acids by transforming them mainly to keto and hydroxy acids, which subsequently were converted to carboxylic acids by the Lactococcus strain. Therefore, we think that such cooperation between starter L. lactis and GDH-positive lactobacilli can stimulate flavor development in cheese.

APA, Harvard, Vancouver, ISO, and other styles

35

Raj, Dominic S. C., Tomas Welbourne, Elizabeth A. Dominic, Debra Waters, Robert Wolfe, and Arny Ferrando. "Glutamine kinetics and protein turnover in end-stage renal disease." American Journal of Physiology-Endocrinology and Metabolism 288, no. 1 (January 2005): E37—E46. http://dx.doi.org/10.1152/ajpendo.00240.2004.

Full text

Abstract:

Alanine and glutamine constitute the two most important nitrogen carriers released from the muscle. We studied the intracellular amino acid transport kinetics and protein turnover in nine end-stage renal disease (ESRD) patients and eight controls by use of stable isotopes of phenylalanine, alanine, and glutamine. The amino acid transport kinetics and protein turnover were calculated with a three-pool model from the amino acid concentrations and enrichment in the artery, vein, and muscle compartments. Muscle protein breakdown was more than synthesis (nmol·min−1·100 ml leg−1) during hemodialysis (HD) (169.8 ± 20.0 vs. 125.9 ± 21.8, P < 0.05) and in controls (126.9 ± 6.9 vs. 98.4 ± 7.5, P < 0.05), but synthesis and catabolism were comparable pre-HD (100.7 ± 15.7 vs. 103.4 ± 14.8). Whole body protein catabolism decreased by 15% during HD. The intracellular appearance of alanine (399.0 ± 47.1 vs. 243.0 ± 34.689) and glutamine (369.7 ± 40.6 vs. 235.6 ± 27.5) from muscle protein breakdown increased during dialysis (nmol·min−1·100 ml leg−1, P < 0.01). However, the de novo synthesis of alanine (3,468.9 ± 572.2 vs. 3,140.5 ± 467.7) and glutamine (1,751.4 ± 82.6 vs. 1,782.2 ± 86.4) did not change significantly intradialysis (nmol·min−1·100 ml leg−1). Branched-chain amino acid catabolism (191.8 ± 63.4 vs. −59.1 ± 42.9) and nonprotein glutamate disposal (347.0 ± 46.3 vs. 222.3 ± 43.6) increased intradialysis compared with pre-HD (nmol·min−1·100 ml leg−1, P < 0.01). The mRNA levels of glutamine synthase (1.45 ± 0.14 vs. 0.33 ± 0.08, P < 0.001) and branched-chain keto acid dehydrogenase-E2 (3.86 ± 0.48 vs. 2.14 ± 0.27, P < 0.05) in the muscle increased during HD. Thus intracellular concentrations of alanine and glutamine are maintained during HD by augmented release of the amino acids from muscle protein catabolism. Although muscle protein breakdown increased intradialysis, the whole body protein catabolism decreased, suggesting central utilization of amino acids released from skeletal muscle.

APA, Harvard, Vancouver, ISO, and other styles

36

Ma, Jin-Tian, Li-Sheng Wang, Zhi Chai, Xin-Feng Chen, Bo-Cheng Tang, Xiang-Long Chen, Cai He, Yan-Dong Wu, and An-Xin Wu. "Access to 2-arylquinazolines via catabolism/reconstruction of amino acids with the insertion of dimethyl sulfoxide." Chemical Communications 57, no. 44 (2021): 5414–17. http://dx.doi.org/10.1039/d1cc00623a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Zinser, Erik R., and Roberto Kolter. "Mutations Enhancing Amino Acid Catabolism Confer a Growth Advantage in Stationary Phase." Journal of Bacteriology 181, no. 18 (September 15, 1999): 5800–5807. http://dx.doi.org/10.1128/jb.181.18.5800-5807.1999.

Full text

Abstract:

ABSTRACT Starved cultures of Escherichia coli undergo successive rounds of population takeovers by mutants of increasing fitness. These mutants express the growth advantage in stationary phase (GASP) phenotype. Previous work identified the rpoS819 allele as a GASP mutation allowing cells to take over stationary-phase cultures after growth in rich media (M. M. Zambrano, D. A. Siegele, M. A. Almirón, A. Tormo, and R. Kolter, Science 259:1757–1760, 1993). Here we have identified three new GASP loci from an aged rpoS819 strain: sgaA, sgaB, and sgaC. Each locus is capable of conferring GASP on therpoS819 parent, and they can provide successively higher fitnesses for the bacteria in the starved cultures. All four GASP mutations isolated thus far allow for faster growth on both individual and mixtures of amino acids. Each mutation confers a growth advantage on a different subset of amino acids, and these mutations act in concert to increase the overall catabolic capacity of the cell. We present a model whereby this enhanced ability to catabolize amino acids is responsible for the fitness gain during carbon starvation, as it may allow GASP mutants to outcompete the parental cells when growing on the amino acids released by dying cells.

APA, Harvard, Vancouver, ISO, and other styles

38

Moraes, Fernanda D., Priscila A. Rossi, Juliana S. L. Figueiredo, Francine P. Venturini, Lucas R. X. Cortella, and Gilberto Moraes. "Metabolic responses of channel catfish (Ictalurus punctatus) exposed to phenol and post-exposure recovery." Anais da Academia Brasileira de Ciências 88, no. 2 (May 31, 2016): 865–75. http://dx.doi.org/10.1590/0001-3765201620150144.

Full text

Abstract:

Metabolic adjustments were studied in channel catfish Ictalurus punctatus exposed to 1.5 mg L-1 of phe nol (10% LC50) for four days and recovered for seven days. Lower triacylglycerol (TGA) stores and increased muscle fat free acids (FFA) suggest fat catabolism in muscle. Remarkable liver FFA decrease (-31%) suggests liver fat catabolism as well. Increased muscular ammonia levels and ASAT (aspartate aminotransferase) and decreased plasma aminoacids suggest higher muscular amino acid uptake. Constant levels of glucose and increased liver glycogen stores, associated with lower amino acids in plasma, indicate gluconeogenesis from amino acids. This is supported by higher hepatic ALAT and ASAT. Higher hepatic LDH followed by lower plasma lactate may indicate that plasma lactate was also used as gluconeogenic substrate. Biochemical alterations were exacerbated during the post-exposure recovery period. Reduction in muscle and plasma protein content indicate proteolysis. A higher rate of liver fat catabolism was resulted from a remarkable decrease in hepatic TGA (-58%). Catabolic preference for lipids was observed in order to supply such elevated energy demand. This study is the first insight about the metabolic profile of I. punctatus to cope with phenol plus its ability to recover, bringing attention to the biological consequences of environmental contamination.

APA, Harvard, Vancouver, ISO, and other styles

39

Grantham, Barbara D., and J. Barrett. "Amino acid catabolism in the nematodes Heligmosomoides polygyrus and Panagrellus redivivus. 1. Removal of the amino group." Parasitology 93, no. 3 (December 1986): 481–93. http://dx.doi.org/10.1017/s0031182000081191.

Full text

Abstract:

SUMMARYThe major transaminase in Heligmosomoides polygyrus, Panagrellus redivivus and rat liver was the 2-oxoglutarate-glutamate system, with relatively few amino acids acting as donors for the pyruvate-alanine and oxaloacetate–aspartate systems. The relative effectiveness of the different amino acid donors in the three transaminase systems was similar in all three tissues. Both H. polygyrus and P. redivivus can oxidatively deaminate a range of L-amino acids, although D-amino acid oxidase activity was low. Serine and threonine dehydratase activity and histidase activity were present in H. polygyrus and P. redivivus and both nematodes were also able to deaminate glutamine, asparagine and arginine. When NAD(H) was the cofactor the glutamate dehydrogenases of H. polygyrus and P. redivivus showed similar regulatory properties to the mammalian enzyme. However, with NADP(H) the results were anomalous. The capacity of both nematodes to transaminate and oxidatively deaminate amino acids was broadly similar and comparable to mammalian tissue. Glutamate dehydrogenase is probably the major route for deamination in these nematodes. A complete sequence of urea cycle enzymes could not be demonstrated in either P. redivivus or H. polygyrus.

APA, Harvard, Vancouver, ISO, and other styles

40

Helinck, Sandra, Dominique Le Bars, Daniel Moreau, and Mireille Yvon. "Ability of Thermophilic Lactic Acid Bacteria To Produce Aroma Compounds from Amino Acids." Applied and Environmental Microbiology 70, no. 7 (July 2004): 3855–61. http://dx.doi.org/10.1128/aem.70.7.3855-3861.2004.

Full text

Abstract:

ABSTRACT Although a large number of key odorants of Swiss-type cheese result from amino acid catabolism, the amino acid catabolic pathways in the bacteria present in these cheeses are not well known. In this study, we compared the in vitro abilities of Lactobacillus delbrueckii subsp. lactis, Lactobacillus helveticus, and Streptococcus thermophilus to produce aroma compounds from three amino acids, leucine, phenylalanine, and methionine, under mid-pH conditions of cheese ripening (pH 5.5), and we investigated the catabolic pathways used by these bacteria. In the three lactic acid bacterial species, amino acid catabolism was initiated by a transamination step, which requires the presence of an α-keto acid such as α-ketoglutarate (α-KG) as the amino group acceptor, and produced α-keto acids. Only S. thermophilus exhibited glutamate dehydrogenase activity, which produces α-KG from glutamate, and consequently only S. thermophilus was capable of catabolizing amino acids in the reaction medium without α-KG addition. In the presence of α-KG, lactobacilli produced much more varied aroma compounds such as acids, aldehydes, and alcohols than S. thermophilus, which mainly produced α-keto acids and a small amount of hydroxy acids and acids. L. helveticus mainly produced acids from phenylalanine and leucine, while L. delbrueckii subsp. lactis produced larger amounts of alcohols and/or aldehydes. Formation of aldehydes, alcohols, and acids from α-keto acids by L. delbrueckii subsp. lactis mainly results from the action of an α-keto acid decarboxylase, which produces aldehydes that are then oxidized or reduced to acids or alcohols. In contrast, the enzyme involved in the α-keto acid conversion to acids in L. helveticus and S. thermophilus is an α-keto acid dehydrogenase that produces acyl coenzymes A.

APA, Harvard, Vancouver, ISO, and other styles

41

Serrazanetti, Diana I., Maurice Ndagijimana, Sylvain L. Sado-Kamdem, Aldo Corsetti, Rudi F. Vogel, Matthias Ehrmann, and M. Elisabetta Guerzoni. "Acid Stress-Mediated Metabolic Shift in Lactobacillus sanfranciscensis LSCE1." Applied and Environmental Microbiology 77, no. 8 (February 18, 2011): 2656–66. http://dx.doi.org/10.1128/aem.01826-10.

Full text

Abstract:

ABSTRACTLactobacillus sanfranciscensisLSCE1 was selected as a target organism originating from recurrently refreshed sourdough to study the metabolic rerouting associated with the acid stress exposure during sourdough fermentation. In particular, the acid stress induced a metabolic shift toward overproduction of 3-methylbutanoic and 2-methylbutanoic acids accompanied by reduced sugar consumption and primary carbohydrate metabolite production. The fate of labeled leucine, the role of different nutrients and precursors, and the expression of the genes involved in branched-chain amino acid (BCAA) catabolism were evaluated at pH 3.6 and 5.8. The novel application of the program XCMS to the solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) data allowed accurate separation and quantification of 2-methylbutanoic and 3-methylbutanoic acids, generally reported as a cumulative datum. The metabolites coming from BCAA catabolism increased up to seven times under acid stress. The gene expression analysis confirmed that some genes associated with BCAA catabolism were overexpressed under acid conditions. The experiment with labeled leucine showed that 2-methylbutanoic acid originated also from leucine. While the overproduction of 3-methylbutanoic acid under acid stress can be attributed to the need to maintain redox balance, the rationale for the production of 2-methylbutanoic acid from leucine can be found in a newly proposed biosynthesis pathway leading to 2-methylbutanoic acid and 3 mol of ATP per mol of leucine. Leucine catabolism to 3-methylbutanoic and 2-methylbutanoic acids suggests that the switch from sugar to amino acid catabolism supports growth inL. sanfranciscensisin restricted environments such as sourdough characterized by acid stress and recurrent carbon starvation.

APA, Harvard, Vancouver, ISO, and other styles

42

Curtin, Áine C., and Paul LH McSweeney. "Catabolism of aromatic amino acids in cheese-related bacteria: aminotransferase and decarboxylase activities." Journal of Dairy Research 70, no. 2 (May 2003): 249–52. http://dx.doi.org/10.1017/s0022029903006186.

Full text

Abstract:

Bacterial decarboxylases and aminotransferases may be involved in the production of flavour or off-flavour compounds from aromatic amino acids during cheese ripening. Transamination is one of the first steps in amino acid catabolism for both lactococci and lactobacilli (Gao et al. 1997; Klein et al. 2001). Biologically active amines, produced by decarboxylation, such as tyramine, phenylethylamine, tryptamine, histamine, cadaverine and putrescine, known as biogenic amines, have been found in cheese and can cause migraine and hypertension in susceptible consumers (McSweeney & Sousa, 2000).

APA, Harvard, Vancouver, ISO, and other styles

43

Schriever, Sonja C., Manuel J. Deutsch, Jerzy Adamski, Adelbert A. Roscher, and Regina Ensenauer. "Cellular signaling of amino acids towards mTORC1 activation in impaired human leucine catabolism." Journal of Nutritional Biochemistry 24, no. 5 (May 2013): 824–31. http://dx.doi.org/10.1016/j.jnutbio.2012.04.018.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Dickinson, J. Richard, L. Eshantha J. Salgado, and Michael J. E. Hewlins. "The Catabolism of Amino Acids to Long Chain and Complex Alcohols inSaccharomyces cerevisiae." Journal of Biological Chemistry 278, no. 10 (December 23, 2002): 8028–34. http://dx.doi.org/10.1074/jbc.m211914200.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

MIYAKOSHI, Shunichi, Kengo ENAMI, Hiroo UCHIYAMA, and Takeshi TABUCHI. "Role of methylcitric acid cycle in catabolism of amino acids by Saccharomycopsis lipolytica." Agricultural and Biological Chemistry 51, no. 4 (1987): 1017–21. http://dx.doi.org/10.1271/bbb1961.51.1017.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Mansour, Soulaf, Julie Bailly, J��r��me Delettre, and Pascal Bonnarme. "A proteomic and transcriptomic view of amino acids catabolism in the yeastYarrowia lipolytica." PROTEOMICS 9, no. 20 (October 2009): 4714–25. http://dx.doi.org/10.1002/pmic.200900161.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Sklan, D., and Y. Noy. "Catabolism and Deposition of Amino Acids in Growing Chicks: Effect of Dietary Supply." Poultry Science 83, no. 6 (June 2004): 952–61. http://dx.doi.org/10.1093/ps/83.6.952.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Miyakoshi, Shunichi, Kengo Enami, Hiroo Uchiyama, and Takeshi Tabuchi. "Role of Methylcitric Acid Cycle in Catabolism of Amino Acids by Saccharomyqppsis lipolytica." Agricultural and Biological Chemistry 51, no. 4 (April 1, 1987): 1017–21. http://dx.doi.org/10.1080/00021369.1987.10868172.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Sun, Haipeng, Gang Lu, Shuxun Ren, Jaunian Chen, and Yibin Wang. "Catabolism of Branched-Chain Amino Acids in Heart Failure: Insights from Genetic Models." Pediatric Cardiology 32, no. 3 (January 7, 2011): 305–10. http://dx.doi.org/10.1007/s00246-010-9856-9.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Moughan, Paul J. "An overview of energy and protein utilisation during growth in simple-stomached animals." Animal Production Science 58, no. 4 (2018): 646. http://dx.doi.org/10.1071/an15791.

Full text

Abstract:

The biological processes underlying the partitioning of amino acids and energy during animal growth are well understood qualitatively. However, if a deeper mechanistic understanding is to be achieved, such as to allow generalised predictions of growth outcomes, these biological processes need to be described quantitatively, along with critical control points. Concepts and rules can be formulated at mechanistic and semi-mechanistic levels, and often reflecting causation, to allow nutrient intake and partitioning to be described in a quantitative manner for different animal and environmental conditions. An overview is given of amino acid and energy partitioning during growth in monogastric animals, in terms of causation and quantitatively based descriptors. Current knowledge is far from complete, and areas requiring new insights and a more in-depth understanding of causative mechanisms include voluntary food-intake control, dynamics of nutrient uptake, temporary post-prandial nutrient storage, relationships among nutrient intakes, protein turnover and maintenance-energy requirement, colonic amino acid uptake in poultry, bioavailability of amino acids other than lysine, diet effects on gut endogenous amino acid loss, inevitable amino acid catabolism, preferential amino acid catabolism, and diet, age and genotype effects on body protein synthesis and degradation.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Catabolism of mammal amino acids'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles