Amino Acid Metabolism in Plants. II. Transamination Reactions of Free Protein Amino Acids in Cell-Free Extracts of Cotyledons and Growing Tissues of Bushbean Seedlings (Phaseolus vulgaris L.)

1972 ◽  
Vol 50 (5) ◽  
pp. 538-542 ◽  
Author(s):  
J. C. Forest ◽  
F. Wightman
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
The Other ◽  
Amino Group ◽  
Phaseolus Vulgaris L ◽  
Keto Acids ◽  
Protein Amino Acids

The different transaminase reactions for 22 protein amino acids were investigated in extracts of cotyledons and growing tissues of 8-day-old bushbean seedlings when either α-ketoglutarate, oxaloacetate, pyruvate, or glyoxylate was used as amino group acceptor. The results indicate that both cotyledons and growing tissues exhibited a similar pattern of transaminase activities with respect to the amino acids normally required for protein synthesis. It was found that with the exception of proline, hydroxyproline, and cystine which did not appear to be transaminated, and of serine and threonine which were transaminated only when pyruvate or glyoxylate was provided as the amino group acceptor, all the other 17 amino acids were transaminated to different extents when each of the four keto acids tested was supplied as the amino group acceptor. Glutamic acid, aspartic acid, and alanine were, by far, the best amino group donors and α-ketoglutarate was generally found to be the best amino acceptor. Consideration is given to the number and substrate specificity of the aminotransferases catalyzing the reactions demonstrated in this study.

Amino acid metabolism of dog jejunum before and during absorption of keto analogues.

1977 ◽  
Vol 232 (3) ◽  
pp. E263
Author(s):  
F L Weber ◽  
W C Maddrey ◽  
M Walser
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Arterial Blood ◽  
Keto Acids ◽  
Significant Release ◽  
Significant Uptake ◽  
Keto Analogues ◽  
Jejunal Wall

In fasting dogs, significant uptake by the jejunal wall from arterial blood was found for glutamine and eight other amino acids. Significant release into the mesenteric vein of ammonium, alanine, citrulline, and proline occurred, equal in nitrogen content to glutamine nitrogen taken up. The keto analogues of leucine, valine, and isoleucine, infused for 1 h into the lumen at initial concentrations of 10mM, disappeared from the lumen at 20.2 +/- 1.6, 18.6 +/- 2.0, and 15.7 +/- 2.8 mumol/cm in 1h, respectively. Eight fifteen and seventeen percent, respectively, of these absorbed quantities were released into mesenteric blood as leucine, valine, and isoleucine plus alloisoleucine, indicating significant amination of the keto acids by the gut wall. No significant changes were detected in the arteriovenous differences of any other amino acids or ammonium. The remainder of the absorbed analogues of valine and isoleucine appeared as such in the blood. In the case of the keto analogue of leucine, there was apparent degradation by the gut wall of 34% of the absorbed compound.

Role of Leucine in Protein Metabolism During Exercise and Recovery

2002 ◽  
Vol 27 (6) ◽  
pp. 646-662 ◽  
Author(s):  
Donald K. Layman
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Branched Chain Amino Acids ◽  
New Findings ◽  
Branched Chain

Exercise produces changes in protein and amino acid metabolism. These changes include degradation of the branched-chain amino acids, production of alanine and glutamine, and changes in protein turnover. One of the amino acid most affected by exercise is the branched-chain amino acid leucine. Recently, there has been an increased understanding of the role of leucine in metabolic regulations and remarkable new findings about the role of leucine in intracellular signaling. Leucine appears to exert a synergistic role with insulin as a regulatory factor in the insulin/phosphatidylinositol-3 kinase (PI3-K) signal cascade. Insulin serves to activate the signal pathway, while leucine is essential to enhance or amplify the signal for protein synthesis at the level of peptide initiation. Studies feeding amino acids or leucine soon after exercise suggest that post-exercise consumption of amino acids stimulates recovery of muscle protein synthesis via translation regulations. This review focuses on the unique roles of leucine in amino acid metabolism in skeletal muscle during and after exercise. Key words: branched-chain amino acids, insulin, protein synthesis, skeletal muscle

Amino acid metabolism in Ancylostoma ceylanicum and Nippostrongylus brasiliensis

1987 ◽  
Vol 61 (1) ◽  
pp. 84-88 ◽  
Author(s):  
Govind Singh ◽  
Suman Gupta ◽  
J. C. Katiyar ◽  
V. M. L Srivastava
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
The Other ◽  
Nippostrongylus Brasiliensis ◽  
Ancylostoma Ceylanicum ◽  
Other Hand

ABSTRACTAncylostoma ceylanicum and Nippostrongylus brasiliensis decarboxylated most of the amino acids examined, but only a few at signficant rates. The former nematode in general possessed higher activites. Striking differences between the two parasites were, however, noticed regarding the metabolism of some of the amino acids. For instance, while alanine followed by asparate produced highest amounts of 14CO2in the presence of A. ceylanicum, proline exhibited maximum decarboxlation in case of N. brasiliensis. Tyrosine, on the other hand, did not libreate detectable CO2with either parasite. Likewise, although large number of amino acids underwent transmination with 2-oxoglutarate, only some of them elicited appreciable activity for any two parasites.

scholarly journals Amino acid metabolism and protein synthesis in lactating rats fed on a liquid diet

1990 ◽  
Vol 270 (1) ◽  
pp. 77-82 ◽  
Author(s):  
T Barber ◽  
J García de la Asunción ◽  
I R Puertes ◽  
J R Viña
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
High Protein ◽  
The Other ◽  
Small Intestinal Mucosa ◽  
Urea Synthesis ◽  
Carbamoyl Phosphate ◽  
Liver Size

1. Amino acid metabolism was studied in control virgin rats, lactating rats and virgin rats protein-pair-fed with the lactating rats (high-protein virgin rats). 2. Urinary excretion of nitrogen and urea was higher in lactating than in control virgin rats, and in high-protein virgin rats it was higher than in lactating rats. 3. The activities of urea-cycle enzymes (units/g) were higher in high-protein virgin than in lactating rats, except for arginase. In lactating rats the activities of carbamoyl-phosphate synthase, ornithine carbamoyltransferase and argininosuccinate synthase were lower than in control virgin rats. When the liver size is considered, the activities in lactating rats were similar to those in high-protein virgin rats, except for arginase. 4. N-Acetylglutamate content was higher in high-protein virgin rats than in the other two groups. 5. The rate of urea synthesis from precursors by isolated hepatocytes was higher in high-protein virgin rats than in the other two groups. 6. The flooding-dose method (L-[4-3H]phenylalanine) for measuring protein synthesis was used. The absolute synthesis rates of mammary gland, liver and small-intestinal mucosa were higher in lactating rats than in the other two groups, and in high-protein virgin rats than in control virgin rats 7. These results show that the increased needs for amino acids during lactation are met by hyperphagia and by a nitrogen-sparing mechanism.

scholarly journals Metabolomics analysis reveals a modified amino acid metabolism that correlates with altered oxygen homeostasis in COVID-19 patients

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
José C. Páez-Franco ◽  
Jiram Torres-Ruiz ◽  
Víctor A. Sosa-Hernández ◽  
Rodrigo Cervantes-Díaz ◽  
Sandra Romero-Ramírez ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Lung Damage ◽  
Amino Acid Supplementation ◽  
Enzymatic Conversion ◽  
Clinical Markers ◽  
Hypoxic Conditions ◽  
Oxygen Homeostasis ◽  
Keto Acids

AbstractWe identified the main changes in serum metabolites associated with severe (n = 46) and mild (n = 19) COVID-19 patients by gas chromatography coupled to mass spectrometry. The modified metabolic profiles were associated to an altered amino acid catabolism in hypoxic conditions. Noteworthy, three α-hydroxyl acids of amino acid origin increased with disease severity and correlated with altered oxygen saturation levels and clinical markers of lung damage. We hypothesize that the enzymatic conversion of α-keto-acids to α- hydroxyl-acids helps to maintain NAD recycling in patients with altered oxygen levels, highlighting the potential relevance of amino acid supplementation during SARS-CoV-2 infection.

Biochemische Aspekte des Aminosäuren-Stoffwechsels bei Psoriasis vulgaris / Biochemical Aspects of Amino Acid Metabolism in Psoriasis vulgaris

1973 ◽  
Vol 28 (7-8) ◽  
pp. 449-451 ◽  
Author(s):  
G. Peter ◽  
H. Angst ◽  
U. Koch
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Psoriasis Vulgaris ◽  
Normal Subjects ◽  
Pathological Process

Free and protein-bound amino acids in serum and scales were investigated. In serum the bound amino acids of psoriatics are significantly higher with exception of Pro, Met, Tyr and Phe in contrast to normal subjects. For free amino acids the differences between normal subjects and psoriatics found in serum and scales are not significant. Results are discussed in relation to the single amino acids and the biochemical correlations are outlined which takes the pathological process as a basis.

scholarly journals BIOSYNTHESIS IN ISOLATED ACETABULARIA CHLOROPLASTS

1972 ◽  
Vol 54 (2) ◽  
pp. 279-294 ◽  
Author(s):  
David C. Shephard ◽  
Wendy B. Levin
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Technical Problems ◽  
Hydrolyzed Protein ◽  
Protein Amino Acids ◽  
Amino Acid Labeling ◽  
Labeling Pattern

The ability of chloroplasts isolated from Acetabulana mediterranea to synthesize the protein amino acids has been investigated. When this chloroplast isolate was presented with 14CO2 for periods of 6–8 hr, tracer was found in essentially all amino acid species of their hydrolyzed protein Phenylalanine labeling was not detected, probably due to technical problems, and hydroxyproline labeling was not tested for The incorporation of 14CO2 into the amino acids is driven by light and, as indicated by the amount of radioactivity lost during ninhydrin decarboxylation on the chromatograms, the amino acids appear to be uniformly labeled. The amino acid labeling pattern of the isolate is similar to that found in plastids labeled with 14CO2 in vivo. The chloroplast isolate did not utilize detectable amounts of externally supplied amino acids in light or, with added adenosine triphosphate (ATP), in darkness. It is concluded that these chloroplasts are a tight cytoplasmic compartment that is independent in supplying the amino acids used for its own protein synthesis. These results are discussed in terms of the role of contaminants in the observed synthesis, the "normalcy" of Acetabularia chloroplasts, the synthetic pathways for amino acids in plastids, and the implications of these observations for cell compartmentation and chloroplast autonomy.

scholarly journals The Diverse Functions of Non-Essential Amino Acids in Cancer

Cancers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 675 ◽  
Author(s):  
Bo-Hyun Choi ◽  
Jonathan L. Coloff
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Cancer Therapy ◽  
Metabolic Pathways ◽  
Essential Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Essential Amino Acids ◽  
Redox Status ◽  
Antioxidant Systems

Far beyond simply being 11 of the 20 amino acids needed for protein synthesis, non-essential amino acids play numerous important roles in tumor metabolism. These diverse functions include providing precursors for the biosynthesis of macromolecules, controlling redox status and antioxidant systems, and serving as substrates for post-translational and epigenetic modifications. This functional diversity has sparked great interest in targeting non-essential amino acid metabolism for cancer therapy and has motivated the development of several therapies that are either already used in the clinic or are currently in clinical trials. In this review, we will discuss the important roles that each of the 11 non-essential amino acids play in cancer, how their metabolic pathways are linked, and how researchers are working to overcome the unique challenges of targeting non-essential amino acid metabolism for cancer therapy.

IDIOPATHIC HYPERGLYCINEMIA: A NEW DISORDER OF AMINO ACID METABOLISM

PEDIATRICS ◽  
1961 ◽  
Vol 27 (4) ◽  
pp. 539-550 ◽  
Author(s):  
William L. Nyhan ◽  
Margaret Borden ◽  
Barton Childs
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Oral Administration ◽  
Dietary Intake ◽  
Urinary Excretion ◽  
Cation Exchange ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Acute Illness ◽  
Progressive Decrease

The amino acids of blood and urine have been investigated using chromatography on cation exchange columns in the study of a patient with idiopathic hyperglycinemia. Marked increases in concentrations of glycine, serine, alanine, isoleucine and valine were found in the plasma. These changes were not reflected in increased excretion of these amino acids in the urine (with the exception of glycine). Restriction of the dietary intake of protein resulted in a decrease in the concentrations of glycine and other amino acids in the blood and urine, and there was a concomitant decrease in the frequency and severity of episodes of acute illness. The oral administration of leucine was found to induce a decrease in the levels of a number of amino acids in the patient and in controls. Continued decrease during the 3 hours of observation was noted for serine, isoleucine and valine. A mild but progressive decrease in threonine concentration was observed in the controls, while in the patient the concentration increased after the administration of leucine. Decreased levels at 1½ hours, returning toward the fasting levels at 3 hours, were observed for alanine, taurine and glycine. These apparently normal responses to leucine loads were not mediated through increase in the urinary excretion of the amino acids involved, and the data are interpreted to indicate entry of these amino acids into cells.

Sign in / Sign up

Export Citation Format

Share Document