Action of proteolytic enzymes on wheat gluten

1968 ◽  
Vol 46 (9) ◽  
pp. 1019-1022 ◽  
Author(s):  
Hung-Ju Yang ◽  
A. G. McCalla
Keyword(s):  
Amino Acids ◽  
Free Amino ◽  
Proteolytic Enzymes ◽  
Wheat Gluten ◽  
Amino Nitrogen ◽  
Protein Nitrogen ◽  
Early Stages ◽  
Mean Size ◽  
Terminal Amino ◽  
The Mean

Papain and trypsin partially hydrolyzed wheat gluten dispersed in 10% sodium salicylate, and pepsin partially hydrolyzed gluten dispersed in aluminium lactate. Trypsin was considerably less effective than either papain or pepsin. Papain produced non-protein nitrogen most rapidly during early stages of hydrolysis but pepsin produced the largest total after 48 h. The rate of release of terminal amino nitrogen was similar for papain and pepsin, and release was not complete after 48 h. The mean size of polypeptides was larger in papain than in pepsin hydrolysates during early stages of hydrolysis but definitely smaller after 48 h. Only pepsin released appreciable amounts of free amino acid nitrogen. Leucine and phenylalanine made up over 50% of the free amino acids after 48 h but several other amino acids were found in significant quantities.

Effect of diet and infusion of volatile fatty acids into the rumen on the concentration of plasma free amino acids in sheep

1982 ◽  
Vol 48 (3) ◽  
pp. 519-526 ◽  
Author(s):  
J. R. Mercer ◽  
E. L. Miller
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino ◽  
Volatile Fatty Acids ◽  
Plasma Concentrations ◽  
Essential Amino Acids ◽  
Protein Nitrogen ◽  
Post Infusion ◽  
Limiting Amino Acid ◽  
The Mean

1. The effect of supplementing barley diets with urea (U), extracted decorticated groundnut meal (GNM) or Peruvian fish meal (PFM) on plasma free amino acid concentrations in sheep have been examined and the first limiting amino acid has been indicated by measuring the changes in the concentration of the plasma essential amino acids (PEAA) during a rumen infusion of a volatile fatty acid (VFA) mixture.2. Three wethers fitted with rumen and re-entrant duodenal cannulas were given isonitrogenous, isoenergetic diets containing (g/kg dry matter (DM)) U 20, GNM 106 or PFM 78, the crude protein (nitrogen × 6.25) contents being 139, 145 and 148 respectively. The sheep were fed hourly, the mean daily dm intake being 0.634 kg.3. Plasma concentrations of valine, threonine, lysine, isoleucine and leucine were linearly related to their concentrations in duodenal digesta.4. A VFA mixture was infused into the rumen for 6 h to supply (mmol/min) acetate 1.47, propionate 0.22 and n-butyrate 0.27. Blood samples were taken 6 h before, during and 12 h after the end of the infusion.5. The concentration of all PEAA decreased relative to the pre-infusion and post-infusion controls but there were no significant differences between diets.6. The mean decreases in concentration averaged over all three diets showed that the decrease in concentration of methionine (41.5%) was far greater than for any other essential amino acid suggesting that under these conditions methionine was the first limiting amino acid.

Effects of Nitrogen Source and Concentration on the Free Amino Acid Composition of Developing Wheat Grains

1990 ◽  
Vol 17 (2) ◽  
pp. 199 ◽  
Author(s):  
C Blumenthal ◽  
JW Lee ◽  
EWR Barlow ◽  
IL Batey
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Ammonium Nitrate ◽  
Amino Acid Composition ◽  
Free Amino Acid ◽  
Acid Composition ◽  
Free Amino ◽  
Amino Nitrogen ◽  
Grain Protein ◽  
Protein Nitrogen

Detached wheat heads (7 days post-anthesis) were grown in liquid culture containing nitrogen concentrations of 0.025% or 0.1% in the form of glutamine, ammonium nitrate or asparagine. With each form of the nitrogen, increasing the concentrations of nitrogen in the culture medium led to increases in the total nitrogen and the non-protein nitrogen in the grain. Protein contents (N × 5.7) were approximately 16% and 21% on a dry weight basis in the low and high treatments respectively for all nitrogen sources. Amino acids from the endosperm cavity, the ethanol-soluble extract of the grain, and the grain protein were analysed by HPLC techniques to define the site of transfer between amino acid forms. The results indicated that amino nitrogen from glutamine, ammonium nitrate, or asparagine enters the grain and is found in the endosperm cavity fluid mainly in the form of glutamine, alanine and, to a lesser extent, aspartate (including asparagine). These amino acids are then converted into the various other amino acids required for protein synthesis, as is demonstrated by the increases found in the others in the ethanol-soluble free amino acid fraction with different nitrogen regimes. These variations in the composition of the free amino acids occurred without altering the amino acid composition of the protein component of the grain.

scholarly journals Evaluating the Authenticity of the Raw-Milk Cheese Fontina (PDO) with Respect to Similar Cheeses

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 350
Author(s):  
Luisa Pellegrino ◽  
Johannes A. Hogenboom ◽  
Veronica Rosi ◽  
Paolo D’Incecco
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Raw Milk ◽  
Manufacturing Processes ◽  
Food Authenticity ◽  
Promising Tool ◽  
Production Area ◽  
The Mean ◽  
Raw Milk Cheese

The implementation of quality assurance schemes for the assessment of PDO food authenticity is an issue involving manufacturers, traders, retailers and consumers. In this respect, reliable analytical methods are needed to integrate paper-trailing information. The feasibility of distinguishing the Italian Fontina PDO cheese from the generic Fontal cheese was preliminarily evaluated on a set of commercial samples by measuring selected parameters (pH, alkaline phosphatase activity, content of copper, volatiles, extent of proteolysis) related to the different manufacturing processes. The relative profile of free amino acids proved to be a promising tool. A new set of 41 samples of Fontina PDO cheese was collected at representative dairies within the recognized production area and analyzed for free amino acids. A chemometric model of Fontina PDO cheese was built based on the mean content and standard deviation of 15 free amino acids. On this basis, all of the PDO samples were correctly identified, whereas all of the Fontal cheeses were recognized as different cheeses.

Free Amino Acid and Haemolymph Concentration Changes in Sphaeroma Rugicauda (Isopoda) During Adaptation to a Dilute Salinity

1969 ◽  
Vol 50 (2) ◽  
pp. 319-326
Author(s):  
R. R. HARRIS
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Sea Water ◽  
Protein Nitrogen ◽  
Body Sodium ◽  
Concentration Changes ◽  
Total Body

1. Non-protein and protein nitrogen fractions of the isopod Sphaeroma rugicauda were measured in animals adapted to 100 and 2% sea water. 2. The non-protein nitrogen component was reduced in animals acclimatized to the lower salinity. 3. Free amino acids accounted for 88 and 74% respectively of the non-protein nitrogen in the two salinities. 4. In 2% sea water taurine, proline, glycine, alanine and glutamic acid showed the greatest decreases in concentration compared to the levels measured in animals adapted to 100% sea water. 5. The decrease in total free amino acids of animals acclimatized to 100% sea water and transferred to 2% sea water was measured. 6. The total free amino acid concentration is reduced to the 2% sea water level within 12 hr. after transfer. 7. Free amino acid, haemolymph sodium and total body sodium levels after transfer to 2% sea water were compared. 8. The asymmetry between the fall in haemolymph sodium concentration and the decrease in total body sodium under these conditions is thought to be due to a water shift from the haemolymph into the tissues. 9. It is suggested that the osmotic pressure of the cells falls at a slower rate than that of the haemolymph.

THE ESTIMATION OF FREE AMINO ACIDS USING A MICRODIFFUSION TECHNIQUE

1952 ◽  
Vol 30 (7) ◽  
pp. 522-528 ◽  
Author(s):  
W. B. McConnell
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
The Other ◽  
Routine Analysis ◽  
Average Deviation ◽  
Substantial Saving ◽  
Ionic Concentrations ◽  
The Mean

The carbon dioxide evolved when α-amino acids were heated for one hour at 85 °C. with ninhydrin was determined in a partially evacuated microdiffusion cell. Distillation of solvent from one chamber to the other was minimized by keeping the ionic concentrations of the reaction mixture and absorbing mixture approximately equal. The method was useful for samples of amino acids which liberated from 0.06 to 0.3 mgm. of carbon dioxide. The average deviation from the mean was somewhat less than 1% for samples liberating 0.2 mgm. of carbon dioxide. Use of the method for routine analysis of enzymatic digests resulted in substantial saving of time and material.

The effect of starvation and low nitrogen intakes on the concentration of free amino acids in the blood plasma and on the nitrogen metabolism in sheep

1970 ◽  
Vol 21 (5) ◽  
pp. 723 ◽  
Author(s):  
J Leibholz
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Dry Matter ◽  
Control Diet ◽  
Amino Nitrogen ◽  
Essential Amino Acids ◽  
Isoleucine Leucine ◽  
Plasma Urea ◽  
Low Nitrogen

Crossbred wethers were given a control diet (8 g nitrogen, 730 g dry matter daily) or a low nitrogen diet (0.5 g nitrogen, 520 g dry matter daily) or starved, for a 12 or 20 day experimental period. The concentrations of free serine, glutamine, glycine, alanine, histidine, and arginine in the plasma of the starved sheep decreased significantly while the concentrations of lysine, 3-methylhistidine, and isoleucine increased significantly. The ratio of essential to non-essential amino acids increased from 0.35 to 0.56 in the starved sheep. In sheep on the low nitrogen diet, the ratio of essential to non-essential amino acids in the plasma decreased from 0.40 to 0.27, with significant increases in the concentrations of glutanlic acid, glutamine, glycine, isoleucine, leucine, and 3-methylhistidine. Starvation and the low nitrogen diet both resulted in a reduction of the plasma urea concentrations. Starvation and the low nitrogen diet resulted in a 20-50 % reduction in the flow of saliva and a 40-78% increase in the concentration of total nitrogen. This resulted in no significant change in the daily secretion of nitrogen in the saliva. The concentration of urea in the saliva was increased by 3-54%. The concentrations of individual free amino acids in saliva are reported. The nitrogen content of the rumen was reduced, and after 7 days of starvation or on the low nitrogen diet all rumen nitrogen could be attributed to ammonia and free �-amino nitrogen.

A study on the degradation of arachin by proteolytic enzymes

1973 ◽  
Vol 51 (11) ◽  
pp. 2217-2222 ◽  
Author(s):  
R. B. van Huystee
Keyword(s):  
Amino Acids ◽  
Proteolytic Activity ◽  
Free Amino Acids ◽  
Free Amino ◽  
Proteolytic Enzymes ◽  
Disc Electrophoresis ◽  
Polyacrylamide Gels ◽  
Macromolecular Protein

The prime purpose of this proteolysis study was to direct attention to alternate means of measuring proteolytic activity other than the determination of free amino acids. The release of peptides from a macromolecular protein during incubation with either papain, pronase, or trypsin was determined by measuring the presence of 280-nm-absorbing molecules in the fractionation range of Sephadex G 25 eluant after incubation. The formation of larger proteinaceous constituents by proteolysis of arachin was analyzed by disc electrophoresis on polyacrylamide gels. Using these techniques it was noted that papain was the most efficient proteolytic agent for the degradation of arachin.

Variations in the concentrations of free amino acids in the plasma of the dairy cow at parturition

1972 ◽  
Vol 39 (3) ◽  
pp. 355-364 ◽  
Author(s):  
R. Verbeke ◽  
E. Roets ◽  
G. Peeters
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino ◽  
Milk Protein ◽  
Sampling Period ◽  
Aminobutyric Acid ◽  
Amino Acid Utilization ◽  
Amino Acid Levels ◽  
The Mean ◽  
Peak Value

SummaryThe plasma levels of individual amino acids were studied in 6 dairy cows from 4 days before to 3 days after calving. During this sampling period, the concentrations of 13 amino acids showed significant changes. The levels of several amino acids were depressed markedly in the sample collected immediately before calving. Following parturition, the concentration of most amino acids gradually returned to values obtained 3 days before calving. The glutamine and alanine contents of the plasma rose to a peak value 1 day after calving and subsequently decreased. The mean concentrations of glycine and α-aminobutyric acid did not change before parturition but rose significantly thereafter. These observations are discussed in terms of amino-acid utilization for milk protein synthesis and gluconeogenesis at the onset of lactation. The changes in plasma amino acid levels appear to be synchronized with those reported for prolactin and progesterone in the 24 h before parturition. This may indicate an important influence of both hormones on the lactogenic process in the cow. The highly significant correlations obtained between the concentrations of 14 individual amino acids are discussed.

Nitrogenous components of human milk: non-protein nitrogen, true protein and free amino acids

2003 ◽  
Vol 81 (3) ◽  
pp. 357-362 ◽  
Author(s):  
Brunella Carratù ◽  
Concetta Boniglia ◽  
Francesco Scalise ◽  
Amalia Maria Ambruzzi ◽  
Elisabetta Sanzini
Keyword(s):  
Amino Acids ◽  
Human Milk ◽  
Free Amino Acids ◽  
Free Amino ◽  
Protein Nitrogen ◽  
True Protein

scholarly journals THE CHEMISTRY OF INSECT HEMOLYMPH

1956 ◽  
Vol 39 (6) ◽  
pp. 853-868 ◽  
Author(s):  
G. R. Wyatt ◽  
T. C. Loughheed ◽  
S. S. Wyatt
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Developmental Stages ◽  
Galleria Mellonella ◽  
Similar Distribution ◽  
Total Acid ◽  
Protein Nitrogen ◽  
Larval Hemolymph

1. Hemolymph was collected for analysis from the silkworm, Bombyx mori, in a series of developmental stages ranging from the second molt to the late pupa. The mean pH of larval hemolymph after collection was found to be 6.45, that of pupal hemolymph, 6.57; in vivo values may be slightly lower. Total dry solids ranged from 5.4 to 10.6 per cent. Total protein ranged from 1.2 to 5.3 per cent, increasing rapidly during the fifth instar. 2. Free amino acids were separated chromatographically and estimated. Of 19 amino acids identified, amounting collectively to 823 to 1497 mg. per 100 ml., glutamine, histidine, and lysine generally occurred in greatest amount. Tryptophan was not detected, and cystine (or cysteine) was found in only one sample. The total free amino acids account for 35 to 55 per cent of the non-protein nitrogen of the plasma. 3. Free sugars, estimated semiquantitatively on chromatograms, comprise glucose, fructose, and sucrose in total amount ranging from about 5 to 40 mg. per 100 ml. Total acid-soluble, ultrafiltrable carbohydrate, estimated as glucose by the anthrone reaction, ranged from 166 to 635 mg. per 100 ml., indicating the presence of low molecular weight sugar derivatives. 4. Inorganic phosphate amounted to 5 to 15 mg. per 100 ml., and acid-soluble organic phosphate to 100 to 200 mg. per 100 ml. The latter fraction includes several substances, of which one was tentatively identified as glucose-6-phosphate and the remainder are as yet unidentified. 5. Single samples of hemolymph were also taken from larvae of the wax moth, Galleria mellonella, and the spruce sawfly, Diprion hercyniae. These contained even higher concentrations of solutes than the silkworm samples, but with a generally similar distribution. The proportions of the free amino acids were different in each species.

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