Biliary catabolism of glutathione and differential reabsorption of its amino acid constituents

1988 ◽  
Vol 254 (1) ◽  
pp. G1-G7 ◽  
Author(s):  
N. Ballatori ◽  
R. Jacob ◽  
C. Barrett ◽  
J. L. Boyer
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Guinea Pigs ◽  
Free Amino Acids ◽  
Free Amino ◽  
Biliary Tree ◽  
Irreversible Inhibitor ◽  
High Degree ◽  
Bile Samples ◽  
Total Amino Acids

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)

scholarly journals Nitrogen Storage and Its Interaction with Carbohydrates of Young Almond Trees in Response to Nitrogen Supply

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 796C-796
Author(s):  
Guihong Bi* ◽  
Carolyn Scagel ◽  
Lailiang Cheng ◽  
Leslie Fuchigami
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Total Amino Acid ◽  
Total N ◽  
N Supply ◽  
N Assimilation ◽  
Predominant Amino Acid ◽  
Total Amino Acids

June-budded `Nonpareil/Nemaguard' almond (Prunus dulcis (Mill) D.A. Webb) trees were fertigated with one of five nitrogen (N) concentrations (0, 5, 10, 15, or 20 mm) in a modified Hoagland's solution from July to September. In October, the trees were sprayed twice with either water or 3% urea, then harvested after natural leaf fall and stored at 2°C. Trees were destructively sampled during winter storage to determine their concentrations of amino acids, protein, and non-structural carbohydrates (TNC). Increasing N supply either via N fertigation during the growing season or with foliar urea applications in the fall increased the concentrations of both free and total amino acids, whereas decreased their C/N ratios. Moreover, as the N supply increased, the proportion of nitrogen stored as free amino acids also increased. However, protein was still the main form of N used for storage. The predominant amino acid in both the free and total amino-acid pools was arginine. Arginin N accounted for an increasing proportion of the total N in both the free and total amino acids as the N supply was increased. However, the proportion of arginine N was higher in the free amino acids than in the total amino acids. A negative relationship was found between total amino acid and non-structural carbohydrate concentrations, suggesting that TNC is increasingly used for N assimilation as the supply of N increases. Urea applications decreased the concentrations of glucose, fructose, and sucrose, but had little influence on concentrations of sorbitol and starch. We conclude that protein is the primary form of storage N, and that arginine is the predominant amino acid. Furthermore, the synthesis of amino acids and proteins comes at the expense of non-structural carbohydrates.

scholarly journals Free and Total Amino Acid Composition of Maturing Seed from Six Peanut (Arachis hypogaea L.) Cultivars

1980 ◽  
Vol 7 (1) ◽  
pp. 32-37 ◽  
Author(s):  
S. M. M. Basha ◽  
J. P. Cherry ◽  
C. T. Young
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Arachis Hypogaea ◽  
Free Amino Acids ◽  
Free Amino ◽  
Dry Weight ◽  
Rate Of Change ◽  
Arachis Hypogaea L ◽  
Peanut Cultivars ◽  
Total Amino Acids

Abstract Maturing seeds of six peanut cultivars (Arachis hypogaea L.) varying in protein content at maturity showed differences in rate of change of dry weight, crude protein, and free and total amino acids. Seeds of the high-protein cultivars increased in dry weight and deposited protein at a more rapid rate between immature and low intermediate stages of maturation than did those of the low- and intermediate-protein cultivars. Free amino acid content in seeds classified as low-intermediate maturity from all cultivars was significantly less than was that of those at the immature stage. The greatest change was in seed of the high-protein group. The rate of change of content of selected free amino acids among seed was different for the three groups of cultivars. Similar observations were noted as the content of select total amino acids increased in maturing seeds. Variations in quantities of free amino acids in immature seeds and differences in the rate at which they are incorporated into proteins of seeds from various cultivars suggest that there is genetic variability in the mechanism for synthesis of selected proteins. These differences also indicate the potential for the development of peanut cultivars having seed with nutritionally desirable protein.

Changes in proteins and free and total amino acids of peanuts (Arachis hypogaea) infected with Aspergillus parasiticus

1975 ◽  
Vol 53 (22) ◽  
pp. 2639-2649 ◽  
Author(s):  
John P. Cherry ◽  
Clyde T. Young ◽  
Larry R. Beuchat
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Arachis Hypogaea ◽  
Free Amino Acids ◽  
Free Amino ◽  
Aspergillus Parasiticus ◽  
Amino Acid Content ◽  
Total Amino Acid ◽  
Sequence Of Events ◽  
Total Amino Acids

Protein and amino acid composition of peanuts (Arachis hypogaea L.) inoculated with Aspergillus parasiticus Speare were compared with those of non-infected seeds during an 18-day test period to determine metabolic changes within this interrelationship. The levels of buffer-soluble proteins of infected peanuts decreased rapidly to quantities much lower than those of non-infected seeds shortly after inoculation. Simultaneously, the levels of insoluble proteins increased to quantities greater than those contained in soluble fractions. Gel electrophoresis of soluble extracts from inoculated peanuts showed that proteins were hydrolyzed to many small-molecular-weight components, which eventually disappeared as fungal growth progressed. A corresponding increase in quantity of most free amino acids was observed shortly after inoculation of the peanuts. Major changes in free amino acid content coincided with substantial alterations of proteins in both soluble and insoluble fractions. These data suggested that inoculation of peanuts with A. parasiticus initiated a sequence of events whereby proteins were hydrolyzed first to small polypeptides and (or) insoluble components, then to free amino acids. After extended periods of infection, levels of free amino acids varied from day to day, suggesting that differential utilization of these components by the fungus was occurring. Quantities of total amino acids in whole seeds and soluble and insoluble fractions were different for non-inoculated and inoculated peanuts. Distinct differences were especially notable among samples of these three fractions of inoculated seeds. Differences in total amino acid contents apparently reflect qualitative and quantitative changes in proteins and (or) polypeptides present in various fractions examined during the infection period.

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.

Liver extract and its free amino acids equally stimulate gastric acid secretion

1980 ◽  
Vol 239 (6) ◽  
pp. G493-G496 ◽  
Author(s):  
E. J. Feldman ◽  
M. I. Grossman
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Free Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Liver Extract ◽  
Amino Acid Mixture ◽  
Acid Mixture

Using intragastric titration in dogs with gastric fistulas, dose-response studies were carried out with liver extract and with a mixture of amino acids that matched the free amino acids found in liver extract. All solutions were adjusted to pH 7.0 and osmolality to 290 mosmol x kg-1. Doses are expressed as the sum of the concentrations of all free amino acids. At each dose studied (free amino acid concentration: 2.8, 5.6, 11, 23, and 45 mM), acid secretion in response to the free amino acid mixture was not significantly different from that of liver extract. The peak response to both liver extract and the free amino acid mixture occurred with the 23-mM dose and represented about 60% of the maximal response to histamine. The serum concentrations of gastrin after liver extract and the amino acid mixture were not significantly different. It is concluded that in dogs with gastric fistula, gastric acid secretion and release of gastrin were not significantly different in response to liver extract and to a mixture of amino acids that simulated the free amino acid content of liver extract.

Effect of Amino Acid Imbalance on Plasma and Tissue Free Amino Acids in the Rat

1968 ◽  
Vol 96 (3) ◽  
pp. 303-318 ◽  
Author(s):  
P. M.-B. Leung ◽  
Q. R. Rogers ◽  
A. E. Harper
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Amino Acid Imbalance

Free amino acids in extracts of cultured skin fibroblasts from patients with various amino acid metabolic disorders

2008 ◽  
Vol 7 (5) ◽  
pp. 421-425 ◽  
Author(s):  
Vivian E. Shih ◽  
Roseann Mandell ◽  
Harvey L. Levy ◽  
John W. Littlefield
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Metabolic Disorders ◽  
Skin Fibroblasts ◽  
Cultured Skin
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