Factors Influencing the Biosynthesis of the Tyrosine-rich Proteins of Wool

The tyrosine content of wool can vary from about 2�3 to 4�4% of the amino acid residues. This variability, which can be attributed mostly to differences in the proportion of high-tyrosine proteins, appears to be partly of genetic and partly of dietary origin, for there are considerable differences in high-tyrosine protein content between the wools from different breeds of sheep and individual sheep of the same breed, and abomasal infusions of zein, maize gluten and wheat gluten strongly repress the synthesis of these proteins. Infusions of an amino acid mixture simulating the composition of zein produced a similar effect to that of zein. No significant reversal of the repression was produced by adding lysine, tryptophan or tyrosine to zein. It is suggested that these inhibitions may result from interference with aromatic amino acid metabolism.

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Effects of graded removal of lysine from an intravenously infused amino acid mixture on lactation performance and mammary amino acid metabolism in lactating goats

Journal of Dairy Science ◽

10.3168/jds.2016-11921 ◽

2017 ◽

Vol 100 (6) ◽

pp. 4552-4564 ◽

Cited By ~ 8

Author(s):

C.L. Guo ◽

Y.T. Li ◽

X.Y. Lin ◽

M.D. Hanigan ◽

Z.G. Yan ◽

...

Keyword(s):

Amino Acid ◽

Amino Acid Metabolism ◽

Acid Metabolism ◽

Amino Acid Mixture ◽

Acid Mixture ◽

Lactation Performance ◽

Lactating Goats

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Dietary amino acids: effect of depletion and recovery on synthesis in vitro in rat skeletal muscle and liver

British Journal Of Nutrition ◽

10.1079/bjn19740009 ◽

1974 ◽

Vol 31 (1) ◽

pp. 67-76 ◽

Cited By ~ 26

Author(s):

P. T. Omstedt ◽

Alexandra Von Der Decken

Keyword(s):

Skeletal Muscle ◽

Amino Acid ◽

Energy Levels ◽

Wheat Gluten ◽

Amino Acid Mixture ◽

Acid Mixture ◽

Amino Acid Mixtures ◽

Wet Weight ◽

Ribosomal Activity

1. Rats were given diets containing 200 g/kg of a complete or incomplete amino acid mixture or of high- or low-quality proteins. After 6 d the amino acid-incorporating activity of ribosomes from skeletal muscle and liver was studied.2. The level of isotope incorporation relative to ribosomal RNA was similar for casein supplemented with methionine and for a complete amino acid mixture with the composition of whole-egg protein. Per wet weight of tissue there was a significant decrease after feeding with the complete amino acid mixture.3. There was a significant decrease in activity after feeding with amino acid mixtures deficient in lysine, methionine or tryptophan. In skeletal muscle, but not in liver, the ribosomal activity was less than that obtained with wheat gluten. Activity per wet weight of both tissues was less than that obtained with wheat gluten.4. Refeeding with methionine for 1 d resulted in complete restoration of ribosomal activity and activity per wet weight in skeletal muscle.5. After lysine deficiency, protein synthesis per unit wet weight of both tissues and ribosomal activity in liver were not restored after 2 d of refeeding. Recovery of ribosomal activity in skeletal muscle was complete after 1 d.6. Rats receiving the 200 g casein/kg diet supplemented with methionine at daily energy levels of 263, 176, 141 and 106 KJ (62.6, 42.1, 33.7 and 25.3 kcal) showed no changes in ribosomal activity, but there was a significant decrease in activity per wet weight when 106 KJ were given.

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The activation of fatty acid metabolism by Vespa amino acid mixture (VAAM) and related nutrients during endurance exercise in mice

Medicine & Science in Sports & Exercise ◽

10.1097/00005768-199711000-00025 ◽

1997 ◽

Vol 29 (11) ◽

pp. 1543,1544

Author(s):

Takashi Abe ◽

Mihoko Inamori ◽

Kouji Iida ◽

Masahiro Tamura ◽

Yoshimi Takiguchi ◽

...

Keyword(s):

Fatty Acid ◽

Amino Acid ◽

Fatty Acid Metabolism ◽

Endurance Exercise ◽

Acid Metabolism ◽

Amino Acid Mixture ◽

Acid Mixture

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Whole-Body Nitrogen and Splanchnic Amino Acid Metabolism Differ in Rats Fed Mixed Diets Containing Casein or Its Corresponding Amino Acid Mixture

Journal of Nutrition ◽

10.1093/jn/131.7.1965 ◽

2001 ◽

Vol 131 (7) ◽

pp. 1965-1972 ◽

Cited By ~ 66

Author(s):

Maren Daenzer ◽

Klaus Jürgen Petzke ◽

Brian J. Bequette ◽

Cornelia C. Metges

Keyword(s):

Amino Acid ◽

Amino Acid Metabolism ◽

Acid Metabolism ◽

Amino Acid Mixture ◽

Whole Body ◽

Acid Mixture

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HYPERGLYCINEMIA WITH KETOACIDOSIS AND LEUKOPENIA

PEDIATRICS ◽

10.1542/peds.39.6.818 ◽

1967 ◽

Vol 39 (6) ◽

pp. 818-828 ◽

Cited By ~ 1

Author(s):

Juan Rodriguez Soriano ◽

Leonard S. Taitz ◽

Laurence Finberg ◽

Chester M. Edelmann

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Protein Intake ◽

Amino Acid Metabolism ◽

Acid Metabolism ◽

Amino Acid Mixture ◽

Acid Mixture ◽

Glycine Metabolism ◽

Biochemical Features

Metabolic investigations are reported in a patient with the clinical and biochemical features of "idiopathic hyperglycinemia." During ketoacidosis elevated concentrations in serum of numerous amino acids were noted, especially leucine, isoleucine, valine, glycine, and lysine. Hyperammonemia was found in association with ketoacidosis. Clinical and biochemical amelioration was induced by restriction of protein intake to 1 gm/kg or less. Although exacerbation was produced by increasing the protein intake to 1.5 gm/kg, the patient was able to tolerate as much as 3.0 gm/kg of an amino acid mixture in which leucine, isoleucine, valine, methionine, and threonine were absent. It is postulated that this disease, in contrast to hyperglycinemia caused by a specific disorder in glycine metabolism, represents a generalized defect in utilization of amino acids resulting in excessive deamination of certain amino acids in the muscle, with consequent hyperammonemia and ketoacidosis. The nature of the defect in amino acid metabolism is unknown.

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Quantitative study in vivo of methionine cycle in humans using [methyl-2H3]- and [1-13C]methionine

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1988.255.3.e322 ◽

1988 ◽

Vol 255 (3) ◽

pp. E322-E331 ◽

Cited By ~ 17

Author(s):

K. J. Storch ◽

D. A. Wagner ◽

J. F. Burke ◽

V. R. Young

Keyword(s):

Amino Acid ◽

Acid Metabolism ◽

Statistical Significance ◽

Amino Acid Mixture ◽

Balance Model ◽

Acid Mixture ◽

Isotopic Data ◽

Fed State ◽

Induced Changes

Kinetic aspects of body methionine (MET) metabolism were examined in healthy young men during the fed and postabsorptive (PA) states. Rates of MET incorporation (S) into and release (B) from body proteins; transmethylation (TM); and remethylation (RM) and transsulfuration (TS) of homocysteine (HCY) were estimated with the aid of a 5-h constant intravenous infusion of [methyl-2H3]- and [1-13C]methionine. The isotopic data (plasma methionine labeling and 13C enrichment of expired air) were submitted to a stochastic model of amino acid metabolism. During the fed state, the subjects (n = 4) received, at 20-min intervals, small isonitrogenous isocaloric meals containing a complete L-amino acid mixture supplying MET at a rate equivalent to 198 mumol.kg body wt-1.day-1. The PA subjects (n = 4) received the isotope after a 10-h overnight fast. For the PA group, the components of MET metabolism were as follows: S, 20 +/- 0.5; B, 24 +/- 0.5; TM, 5.8 +/- 0.6; RM, 1.8 +/- 0.4; and TS, 4.0 +/- 0.4 (+/-SE) mumol.kg-1.h-1. During the fed state the values were S, 26 +/- 2.5; B, 18 +/- 2; TM, 14 +/- 1.3; RM, 5.7 +/- 0.9; and TS 8.3 +/- 0.6 mumol.kg-1.h-1. The meal-induced changes in B, TM, RM, and TS were significant (P less than 0.05). Comparison of the partitioning of MET between S and TM (these two pathways of MET disposal constitute the "methionine locus") in the PA and in the fed states indicates that the MET locus is of regulatory importance in MET homeostasis. A twofold increase in the partitioning of MET to TM was observed in the fed state. The increase in HCY recycling, relative to TS (these two pathways of HCY disposal constitute the "HCY locus"), in the fed state did not reach statistical significance when compared with the PA state. Total daily TM are estimated to be 238 +/- 22 mumol/kg. This is similar to the estimate generated by the methyl balance model of Mudd and Poole (Metabolism 24: 721, 1975) which approximated 241 mumol/kg.

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Effect of Glycylglycine on Absorption from Human Jejunum of an Amino Acid Mixture Simulating Casein and a Partial Enzymic Hydrolysate of Casein Containing Small Peptides

Clinical Science ◽

10.1042/cs0530027 ◽

1977 ◽

Vol 53 (1) ◽

pp. 27-33

Author(s):

P. D. Fairclough ◽

D. B. A. Silk ◽

M. L. Clark ◽

D. M. Matthews ◽

T. C. Marrs ◽

...

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Glutamic Acid ◽

Free Amino Acids ◽

Free Amino ◽

Amino Acid Mixture ◽

Acid Mixture ◽

Acid Uptake ◽

Amino Acid Residues ◽

Small Peptides

1. A jejunal perfusion technique has been used in normal volunteer subjects to study jejunal absorption of amino acid residues from a partial enzymic hydrolysate of casein in which about 50% of the amino acids existed as small peptides, and also from an equivalent mixture of free amino acids. 2. The effect of a high concentration of the dipeptide glycylglycine on the absorption of amino acid residues from these preparations was studied to quantify the importance of mucosal uptake of intact peptides during absorption of the partial hydrolysate of casein. 3. The results were unexpected. Glycylglycine significantly inhibited absorption of several amino acid residues (aspartic acid + asparagine, serine, glutamic acid + glutamine, proline, alanine, phenylalanine, threonine and isoleucine) from the free amino acid mixture, whereas it significantly inhibited the absorption of only two (serine, glutamic acid + glutamine) from the peptide-containing partial casein hydrolysate. 4. The effect of glycylglycine on absorption of amino acids from the mixture of free amino acids was apparently due to inhibition of amino acid uptake by free glycine liberated from the dipeptide during perfusion. The reason for the failure of glycylglycine to cause extensive inhibition of absorption from the partial hydrolysate is not clear. It may be due to glycylglycine being only a weak inhibitor of peptide uptake, but the possibility that some peptides are taken up by a system unavailable to glycylglycine has to be considered.

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