Concentrations of endogenous free amino acids in rabbit reticulocyte lysates and the effect of incubation

1986 ◽  
Vol 6 (5) ◽  
pp. 429-434 ◽  
Author(s):  
Vasek A. Mezl ◽  
Jane Wall
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Translation System ◽  
Prolonged Storage ◽  
Translation Product ◽  
Radioactive Precursor ◽  
Reticulocyte Lysates ◽  
Amino Acid Concentrations

Amino acid analyses show that while the free amino acids found in the rabbit reticulocyte translation system do not increase during nuclease treatment or during prolonged storage, the endogenous levels of many amino acids are so high that the choice of a radioactive; precursor for a translation should be based not only on the abundance of the amino acid in the translation product but also on its concentration in the lysate preparation. It is shown that the variation of amino acid concentrations between different lysates is sufficiently small to allow one to use the concentrations reported in this study to calculate the amount of radioactive amino acid necessary for satisfactory incorporation.

EFFECT OF CORTISOL TREATMENT ON FREE AMINO ACID LEVELS IN RATS

1973 ◽  
Vol 59 (1) ◽  
pp. 57-63 ◽  
Author(s):  
W. DE LOECKER ◽  
M. L. STAS
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acid ◽  
Protein Turnover ◽  
Free Amino Acids ◽  
Free Amino ◽  
Experimental Period ◽  
Amino Acid Levels ◽  
Amino Acid Concentrations

SUMMARY Changes in the concentrations of free amino acids in intracellular fluids and blood plasma were measured in rats treated with cortisol. Increasing age raised the concentrations of free amino acids in plasma, while in liver, with the exception of glycine and alanine, decreased concentrations were observed. Cortisol treatment reduced free amino acid levels in plasma and liver which suggested a progressive catabolism of body proteins and increased protein synthesis in the liver. In skeletal muscle of control rats the free amino acid concentrations increased during the experimental period. Cortisol increased the concentration of certain amino acids and decreased that of others due to an increased protein turnover in muscle.

ION EXCHANGE CHROMATOGRAPHY OF THE FREE AMINO ACIDS IN THE PLASMA OF INFANTS UNDER 2,500 GM AT BIRTH

PEDIATRICS ◽  
1970 ◽  
Vol 45 (4) ◽  
pp. 606-613
Author(s):  
Johanne C. Dickinson ◽  
Herman Rosenblum ◽  
Paul B. Hamilton
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Ion Exchange ◽  
Free Amino Acids ◽  
Free Amino ◽  
High Sensitivity ◽  
Exchange Chromatography ◽  
Chromatographic Technique ◽  
The Individual ◽  
Amino Acid Concentrations

The free amino acids in the plasma of 46 infants who were under 2,500 gm at birth were determined by an ion exchange chromatographic technique of high sensitivity and resolution. Ninety-two plasma samples were collected from the 46 infants on different days after birth, and the data for 23 amino acids plus taurine and ethanolamine were summarized and compared with newborn, full-term and adult levels. In 16 cases tyrosine levels were high; these values are listed separately. With respect to the remaining amino acids, many showed marked changes during the first few postnatal days; but, by the end of the first week, stable patterns had developed. The decrease or increase of the individual amino acid concentrations in these infants compared to infants with birth weights over 2,500 gm and to the adult was not great and seemed to be characteristic for each amino acid. Attention was drawn to the technical details of preparing and analyzing physiological fluids which would minimize the changes in amino acid concentrations resulting from improper handling.

Free amino acid concentrations in needles of Norway spruce and Scots pine trees on different sites in areas with two levels of nitrogen deposition

1990 ◽  
Vol 20 (8) ◽  
pp. 1132-1136 ◽  
Author(s):  
Ann-Britt Edfast ◽  
Torgny Näsholm ◽  
Anders Ericsson
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Nitrogen Deposition ◽  
Free Amino Acids ◽  
Free Amino ◽  
Aminobutyric Acid ◽  
Site Quality ◽  
Southern Sweden ◽  
Amino Acid Concentrations

The effects of nitrogen deposition and site quality on amino acid concentrations in needles of Piceaabies (L.) Karst. and Pinussylvestris L. trees were studied in two areas that represent different levels of nitrogen deposition: one area in southern Sweden and one area in northern Sweden receive, respectively, approximately 20–30 and 3 kg•ha−1•year−1 of nitrogen. On each area three site quality classes were chosen for each tree species. The site classes were chosen to represent poor, medium, and good sites typical for each area. Free amino acids in the needles were analyzed as 9-fluorenylmethyl formate derivatives by high-performance liquid chromatography. The total nitrogen was determined with a CHN elemental analyzer, and other mineral nutrients were determined with an inductively coupled plasma analyzer. Arginine, glutamic acid, glutamine, γ-aminobutyric acid, and aspartic acid were the quantitatively dominating amino acids in the needles of both species from all sites in both northern and southern Sweden. These amino acids represented 50–80% of the total concentration of free amino acids in the needles. The concentration of arginine in the needles of both spruce and pine increased with decreasing site index and showed high variations between individual trees. For both species, the highest concentrations of arginine were found in the southern area, which had the highest deposition of nitrogen. Concentrations of glutamic acid, glutamine, and γ-aminobutyric acid in the needles of both species showed significant differences between some of the sites on both areas, but these differences showed no general pattern that correlated with the site indexes. In relation to nitrogen, low concentrations of phosphorus and potassium were found in needles from the poorest spruce sites in both areas compared with corresponding values for the good spruce sites. The results are discussed in relation to nitrogen deposition and mineral nutrient imbalance.

Effect of exercise on amino acid concentrations in skeletal muscle and plasma

1991 ◽  
Vol 160 (1) ◽  
pp. 149-165
Author(s):  
J. Henriksson
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Prolonged Exercise ◽  
Exercise Bout ◽  
Current Data ◽  
Short Term ◽  
Exercise Induced ◽  
Amino Acid Concentrations

Protein is not normally an important energy fuel for exercising muscle. In spite of this, there is a significant increase in the rate of amino acid catabolism during exercise. This is secondary to the exercise-induced increase in several metabolic processes, such as hepatic gluconeogenesis and the citric acid cycle, where amino acid carbon is utilized. The suppression of protein synthesis during an exercise bout leaves amino acids available for catabolism. There is some evidence that basal amino acid concentrations in plasma and muscle may be higher in trained than in untrained individuals. In the rat, the concentration of free amino acids is higher in slow-twitch than in fast-twitch muscles. With short-term exercise, the transamination of glutamate by alanine aminotransferase leads to increased levels of alanine in muscle and plasma, and an increased release of alanine from the muscle. At the same time, the muscle and plasma glutamate concentrations are markedly decreased. The plasma glutamine level is elevated with short-term exercise, but changes in muscle glutamine concentration are more variable. With prolonged exercise, there is a depletion of the plasma amino acid pool, which may be explained by an increased consumption in organs other than muscle. With the exception of alanine, we found, however, that the muscle levels of free amino acids are kept stable throughout a 3.5-h exercise period. There is a significant activation of branched-chain amino acid metabolism with prolonged exercise, and the current data indicate that this is more pronounced in endurance-trained subjects than in untrained controls.

The role of free amino acids in cellular osmoregulation in the freshwater bivalve Ligumia subrostrata (Say)

1976 ◽  
Vol 54 (11) ◽  
pp. 1927-1931 ◽  
Author(s):  
J. Alison Hanson ◽  
Thomas H. Dietz
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Pond Water ◽  
Freshwater Bivalve ◽  
Cellular Volume ◽  
Amino Acid Concentrations

Free amino acids constitute 11% of the cellular solute in Ligumia subrostrata acclimated in pond water but less than 1% of blood total solute. Arginine, glutamate, histidine, and alanine account for 60% of the cellular free amino acid concentration. Tissue free amino acid concentrations increase when the animals are exposed to dehydration and anoxic stress. Free amino acids contributing most to the elevated tissue amino acid concentrations are glutamate, alanine, threonine, and serine. These specific free amino acids play an important role in cellular volume regulation.

Plant capture of free amino acids is maximized under high soil amino acid concentrations

2005 ◽  
Vol 37 (1) ◽  
pp. 179-181 ◽  
Author(s):  
David L. Jones ◽  
David Shannon ◽  
Thippaya Junvee-Fortune ◽  
John F. Farrar
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
High Soil ◽  
Amino Acid Concentrations

scholarly journals The digestion and absorption of protein in man

1970 ◽  
Vol 24 (1) ◽  
pp. 241-258 ◽  
Author(s):  
S. Elizabeth Nixon ◽  
G. E. Mawer
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Milk Protein ◽  
Free Form ◽  
Protein Meal ◽  
Intestinal Contents ◽  
Amino Acid Concentrations

1. Intestinal contents, collected from the human jejunum after a test meal (milk-protein, gelatin or low-protein) were fractionated by centrifugation and gel filtration on G-75Sephadex. The fractions were hydrolysed and the proportion of the total amino acid in each fraction was determined. The amino acids were measured with an EEL Amino Acid Analyser.2. The free amino acid concentrations were determined in samples of the contents of the small intestine collected from various levels after the three types of test meal.3. Intestinal contents collected from two levels of the jejunum after a milk-protein meal, were incubated in vitro at 37° for periods up to 80 min and the rates of release of the individual free amino acids were determined.4. There was a rapid breakdown of the proteins of the test meals to fragments of molecular weight under 5000. The further breakdown (during incubation in vitro) to free amino acids was sufficiently rapid to account for the absorption in the free form of arginine, lysine, tyrosine, valine, phenylalanine, methionine and leucine. It was not rapid enough to account for the absorption of glycine, threonine, serine, the imino acids or the dicarboxylic amino acids in the free form.5. The free amino acid concentrations in the intestinal lumen bore very little relationship to the concentrations in hydrolysates of the test meals or to those in hydrolysates of the intestinal contents. Many of the free amino acids in the intestinal samples were present in approximately equimolar concentrations.6. It is suggested that experiments in which amino acid mixtures, simulating a dietary protein, are fed to experimental animals to determine the rates of amino acid absorption do not present a true picture of the events in the small intestine following the ingestion of a protein meal.

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