Oxidation of Free Amino Acids and Amino Acid Residues in Proteins by Radiolysis and by Metal-Catalyzed Reactions

1993 ◽  
Vol 62 (1) ◽  
pp. 797-821 ◽  
Author(s):  
E. R. Stadtman
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Amino Acid Residues ◽  
Catalyzed Reactions ◽  
Metal Catalyzed

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

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.

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.

Effects of abomasal infusions of sodium caseinate, a hydrolysate of casein or a corresponding mixture of free amino acids on milk yield and composition in dairy cows

1995 ◽  
Vol 62 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Jai-Jun Choung ◽  
David G. Chamberlain
Keyword(s):  
Amino Acids ◽  
Dairy Cows ◽  
Free Amino Acids ◽  
Free Amino ◽  
Milk Protein ◽  
Bioactive Peptides ◽  
Basal Diet ◽  
Sodium Caseinate ◽  
Amino Acid Residues ◽  
Kinetics Of

SummaryThe effects of the form in which amino acids are presented to the abomasum on the milk production of dairy cows receiving a basal diet of grass silage and a barley-based supplement were examined in two experiments. Effects of abomasal infusions of sodium caseinate were compared with the effects of corresponding levels of either an enzymic hydrolysate of casein (Expt 1) or a corresponding mixture of free amino acids (FAA; Expt 2). In Expt 1, although the yield of protein in milk increased progressively with each level of infusion, the yields of protein were greater for the caseinate than for the hydrolysate. Again, in Expt 2, for milk protein yield, sodium caseinate was superior to FAA at the lower level of infusion. In both experiments, the hydrolysate and FAA treatments were associated with higher concentrations of fat in the milk. There were indications of differences in the pattern of secretion of glucagon between the caseinate and FAA treatments. It is concluded that the differences between treatments relate either to the kinetics of absorption of amino acid residues or to the action of bioactive peptides released during digestion of casein.

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

scholarly journals Changes in flavor compounds of Aloididae aloidi during enzymatic hydrolysis

2021 ◽  
Vol 233 ◽  
pp. 02040
Author(s):  
Xuting Bai ◽  
Tao Li ◽  
Honglei Zhao ◽  
Xuepeng Li ◽  
Wenhui Zhu ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Enzymatic Hydrolysis ◽  
Free Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Flavor Compounds ◽  
Peptide Analysis ◽  
Soluble Peptide ◽  
Maximum Value

Protamex was selected to prepare the hydrolysate. E-tongue, free amino acid combined with soluble peptide analysis were used to detect the flavor changes of Aloididae aloidi during enzymolysis. Degree of proteolysis increased with the prolongation of enzymolysis time, and reached the maximum value at 8 hours. The content of soluble peptide of hydrolysate increased firstly and then decreased in the later process. The E-tongue could effectively distinguish the taste difference of hydrolysates at different enzymolysis time, and the hydrolysate presented strong bitterness and astringency during the whole enzymolysis. The total amount of free amino acids in the hydrolysate increased gradually, and some sweet, umami and bitter amino acids increased in varying degrees during the process of enzymolysis.

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