D-Mannitol Interferes with Amino Acid Analysis of Marine Organisms

1979 ◽  
Vol 36 (9) ◽  
pp. 1134-1137 ◽  
Author(s):  
W. Fong ◽  
R. K. O'dor
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acid Hydrolysis ◽  
Key Words ◽  
Amino Acid Analysis ◽  
Chromatographic Analysis ◽  
Marine Algae ◽  
Protein S ◽  
New Compounds ◽  
Hydrolysis Of

Acid hydrolysis of a protein in the presence of D-mannitol, a common constituent of marine algae, can cause significant reductions in the recovery of a number of amino acids. The new compounds formed by the interactions of D-mannitol and these amino acids may interfere in the chromatographic analysis of other amino acids. The recoveries of most of the amino acids appear to be either directly or inversely proportional to the amount of D-mannitol added to a protein sample before acid hydrolysis. These results suggest that it is necessary to determine the effects of contaminants in a sample of protein(s) on the recoveries of amino acids during routine acid hydrolysis. Key words: kelp, amino acids, carbohydrates, D-mannitol

scholarly journals Absorption of Chemically Unmodified Lysine from Proteins in Foods That Have Sustained Damage During Processing or Storage

2005 ◽  
Vol 88 (3) ◽  
pp. 949-954 ◽  
Author(s):  
Paul J Moughan
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acid Hydrolysis ◽  
Acid Content ◽  
Amino Acid Analysis ◽  
Amino Acid Content ◽  
Food Proteins ◽  
New Compounds

Abstract When a food is processed or stored, amino acids can react with a number of chemical entities to produce new compounds that are often nutritionally unavailable to the consumer. During acid hydrolysis used in amino acid analysis, some of these compounds revert back to the parent amino acid, leading to errors in estimates of both the amino acid content of foods and amino acid digestibility. This is a particular concern for the amino acid lysine in damaged food proteins. Chemical assays have thus been developed to allow determination of unaltered or reactive lysine. However, there is evidence that, in damaged food proteins, not all of the reactive lysine is released during digestion and absorbed. The development and application of an assay for absorbed (ileal digestible) reactive lysine is discussed.

Hydrolysis of Proteins for Amino Acid Analysis. II. Acid Hydrolysis in Sealed Tubes of Mixtures of β-Lactoglobulin and Starch

1964 ◽  
Vol 47 (4) ◽  
pp. 745-747 ◽  
Author(s):  
William G Gordon ◽  
Jay J Basch
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acid Hydrolysis ◽  
Amino Acid Analysis ◽  
Special Method ◽  
Large Excess ◽  
Β Lactoglobulin ◽  
Hydrolysis Of

Abstract Experiments with a mixture of β-Iactoglobulin and starch, simulating the composition of carbohydrate-rich foods and feeds, have been carried out to determine conditions for acid hydrolysis that will permit maximal recovery of amino acids in hydrolysates of such materials. When a large excess of 6N HC1 is used for hydrolysis, good recoveries of most amino acids are obtained. However, about one-quarter of the tyrosine present is destroyed under the conditions investigated. Some destruction of methionine and cystine may also be attributed to the presence of carbohydrate, but a special method for the determination of these amino acids is available.

scholarly journals Hydrolysis of the Peptide Bond and Amino Acid Modification with Hydriodic Acid

1971 ◽  
Vol 24 (4) ◽  
pp. 1235 ◽  
Author(s):  
AS Inglis ◽  
PW Nicholls ◽  
CM Roxburgh
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Boiling Point ◽  
Amino Acid Analysis ◽  
Peptide Bond ◽  
Hydriodic Acid ◽  
Acid Modification ◽  
Amino Acid Modification ◽  
Hydrolysis Of

Reaction of hydriodic acid with peptides and proteins has been studied. At the boiling point, hydrolysis of the peptide bond, particularly stable bonds linking valine and isoleucine residues, is facile. Several amino acids react with constantboiling hydriodic acid but the only reactions detrimental to the amino acid analysis are the reduction of serine with concomitant formation of alanine, and the destruction of tryptophan. Gentler conditions of hydrolysis with diluted hydriodic acid are required for analysis of serine. Good results for analysis of proteins for amino acids may be obtained after a 6-hr hydrolysis period.

A comparison of methods for determining the concentration of extracellular peptides in rumen fluid of sheep

1990 ◽  
Vol 114 (1) ◽  
pp. 101-105 ◽  
Author(s):  
R. J. Wallace ◽  
N. McKain
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Analysis ◽  
Rumen Fluid ◽  
Amino Acid Content ◽  
Reliable Estimate ◽  
Precipitate Protein ◽  
Micro Organisms ◽  
Hydrolysis Of ◽  
Amino Acid Concentrations

SUMMARYSamples of rumen fluid were removed from pairs of sheep on four grass-hay-based diets 7 h after feeding. Micro-organisms were sedimented by centrifugation and the cell-free supernatant was treated with perchloric acid (PCA) to precipitate protein. The remaining fluid was analysed for peptides by several methods to determine how much peptide escaped degradation. Ammonia interfered with analysis by amino group reagents, especially ninhydrin. In this respect,o-phthalaldehyde and trinitrobenzene sulphonic acid were more specific and more useful than ninhydrin. Use of all these reagents showed that significant quantities of amino groups (equivalent to up to 153 mg amino acid N/1 of rumen fluid) were released by hydrolysis of the PCA extract with 6 M-HCI for 24 h. However, fluorescamine analysis indicated that the peptide content of the unhydrolysed PCA extract was < 3 mg N/1. The true amino acid content of different extracts was resolved by chromatographic amino acid analysis: the sum of individual amino acid concentrations in acid-hydrolysed PCA extracts of extracellular rumen fluid ranged from 7·8 to 14·5 mg N/1. Thus most of the free amino N released by hydrolysis of the PCA extract was not from amino acids, and most of the amino acids that were released were originally present in a form that did not react with fluorescamine. Although none of the methods gave a reliable estimate of peptide concentrations, amino acid analysis provided an upper limit. It was therefore concluded that peptide concentrations in extracellular rumen fluid are much lower than indicated by previous ninhydrin estimations, and that little dietary peptide escapes degradation for a prolonged period in the rumen.

ACTION OF PROTEOLYTIC ENZYMES ON SOIL ORGANIC MATTER

1970 ◽  
Vol 50 (2) ◽  
pp. 233-241 ◽  
Author(s):  
F. J. SOWDEN
Keyword(s):  
Amino Acids ◽  
Organic Matter ◽  
Amino Acid ◽  
Soil Organic Matter ◽  
Acid Hydrolysis ◽  
Leucine Aminopeptidase ◽  
Proteolytic Enzymes ◽  
Complexing Agent ◽  
Organic Matter Fractions ◽  
Hydrolysis Of

The amino acids set free by proteolytic enzymes were determined with an amino acid analyzer. Soil and enzyme blanks were subtracted. Pronase released 2 to 10% of the aspartic acid + asparagine, threonine, serine, glutamic acid + glutamine, glycine, lysine and histidine in some fractions of soil organic matter along with 15–35% of the alanine, valine, isoleucine, leucine, tyrosine, phenylalanine and arginine. There was no release of proline, ornithine or ammonia. When the pronase hydrolysate was treated with leucine amino-peptidase, 15% of the proline was released, the yield of glycine was raised from 2 to 14% and the amount of the acidic amino acids was also higher. Acid hydrolysis of the pronase hydrolysate also released more amino acid material but the blanks were much higher than with leucine aminopeptidase. The results suggested that more than half of the aspartic and glutamic acids found on acid hydrolysis were present in the soil organic matter fractions as asparagine and glutamine. The action of pronase on the organic matter of the intact soil was slight, even in the presence of a complexing agent. Papain released very little amino acid material from organic matter fractions, but leucine aminopeptidase or HCl hydrolysis of the papain hydrolysate released about 10% of the amino acid of the fraction, indicating that significant amounts of peptides were formed on papain treatment.

Amino acid composition of casein isolated from the milks of different species

1977 ◽  
Vol 55 (1) ◽  
pp. 231-236 ◽  
Author(s):  
Bruce H. Lauer ◽  
Bruce E. Baker
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Hydrolysis ◽  
Acid Composition ◽  
Chromatographic Analysis ◽  
Polar Bear ◽  
The Other ◽  
Fin Whale ◽  
Musk Ox

Casein was isolated from the milks of the following species: cow, horse, pig, reindeer, caribou, moose, harp seal, musk-ox, polar bear, dall sheep, and fin whale. The caseins were subjected to acid hydrolysis, the resultant amino acids were converted to their n-butyl-N-trifluoroacetyl esters, and the amino acid composition of the caseins was determined by gas chromatographic analysis of these esters. Notable among the results was the close similarity, with respect to amino acid composition, of reindeer and caribou caseins. The results of the amino acid analyses of the other caseins are presented and discussed.

scholarly journals Available versus digestible dietary amino acids

2012 ◽  
Vol 108 (S2) ◽  
pp. S298-S305 ◽  
Author(s):  
Shane M. Rutherfurd ◽  
Paul J. Moughan
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acid Hydrolysis ◽  
Acid Content ◽  
Amino Acid Analysis ◽  
Amino Acid Content ◽  
Cysteic Acid ◽  
Processed Foods ◽  
Dietary Amino Acids ◽  
Available Lysine

Available amino acids are those absorbed from the gastrointestinal tract in a form suitable for body protein synthesis. True ileal digestible amino acids are determined based on the difference between dietary amino acid intake and unabsorbed dietary amino acids at the terminal ileum. The accuracy of ileal digestible amino acid estimates for predicting available amino acid content depends on several factors, including the accuracy of the amino acid analysis procedure. In heat processed foods, lysine can react with compounds to form nutritionally unavailable derivatives that are unstable during the hydrochloric acid hydrolysis step of amino acid analysis and can revert back to lysine causing an overestimate of available lysine. Recently, the true ileal digestible reactive (available) lysine assay based on guanidination has provided a means of accurately determining available lysine in processed foods. Methionine can be oxidised during processing to form methionine sulphoxide and methionine sulphone and cysteine oxidised to cysteic acid. Methionine sulphoxide, but not methionine sulphone or cysteic acid, is partially nutritionally available in some species of animal. Currently, methionine and cysteine are determined as methionine sulphone and cysteic acid respectively after quantitative oxidation prior to acid hydrolysis. Consequently, methionine and cysteine are overestimated if methionine sulphone or cysteic acid are present in the original material. Overall, given the problems associated with the analysis of some amino acids in processed foodstuffs, the available amino acid content may not always be accurately predicted by true ileal amino acid digestibility estimates. For such amino acids specific analytical strategies may be required.

Improved purification and further characterization of Clostridium perfringens type A enterotoxin

1973 ◽  
Vol 19 (11) ◽  
pp. 1379-1382 ◽  
Author(s):  
A. H. W. Hauschild ◽  
R. Hilsheimer ◽  
W. G. Martin
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Clostridium Perfringens ◽  
Amino Acid Analysis ◽  
Sedimentation Coefficient ◽  
Type A ◽  
Sedimentation Equilibrium ◽  
Molecular Weights ◽  
Hydrolysis Of

The procedure for the purification of Clostridium perfringens type A enterotoxin was simplified, and the purity of the toxin was improved. Hydrolysis of the toxin by the p-toluenesulfonic acid procedure yielded 18 common amino acids. Among these, aspartic acid, serine, leucine, and glutamic acid were the predominant components. The sedimentation coefficient (s°20, w) was 2.8 Svedberg units. The molecular weights determined by the Archibald technique, sedimentation equilibrium, and amino acid analysis were 40 000, 36 000, and 33 000, respectively.

A kinetic study of the acid autoxidation of tryptophan

1972 ◽  
Vol 25 (10) ◽  
pp. 2139 ◽  
Author(s):  
M Stewart ◽  
CH Nicholls
Keyword(s):  
Free Radical ◽  
Amino Acid ◽  
Kinetic Study ◽  
Acid Hydrolysis ◽  
Soda Glass ◽  
Glass Containers ◽  
Hydrolysis Of

The decomposition of tryptophan in aqueous HC1 at 100�C has been shown to proceed by a free-radical autoxidation mechanism. The acid functions by protonating the amino acid at either the 1- or 3-positions prior to autoxidation and so 1-methyltryptophan is also decomposed under these conditions. Impurities present in the soda glass containers used are shown to be responsible for the initiation of the reaction. The decomposition of tryptophan during the acid hydrolysis of proteins is considered in the light of these results.

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