scholarly journals Determination of Sulfur Amino Acids in Foods as Related to Bioavailability

2008 ◽  
Vol 91 (4) ◽  
pp. 907-913 ◽  
Author(s):  
Shane M Rutherfurd ◽  
Paul J Moughan
Keyword(s):  
Methionine Sulfoxide ◽  
Performic Acid ◽  
Cysteic Acid ◽  
Acid Oxidation ◽  
Separate Determination ◽  
Sulfur Amino Acids ◽  
Methionine Sulfone ◽  
Quantitative Impact ◽  
Selection Of

Abstract During the processing of feedstuffs and foods, methionine can be oxidized to methionine sulfoxide and methionine sulfone, and cysteine can be oxidized to cysteic acid. Methionine sulfone and cysteic acid are nutritionally unavailable, but methionine sulfoxide can be utilized, at least to some degree. The degree of utilization depends on the levels of methionine, cysteine, and methionine sulfoxide in the diet, but there is no consensus in the literature on the quantitative impact of these dietary constituents on methionine sulfoxide utilization. Methionine and cysteine are most often determined after quantitative oxidation to methionine sulfone and cysteic acid, respectively, using performic acid oxidation prior to hydrolysis. However, this method may overestimate the methionine content of processed foods, as it will include any methionine sulfoxide and methionine sulfone present. A selection of analytical methods has been developed to allow the separate determination of the 3 oxidized forms of methionine, the merits of which are discussed in this review. An additional consideration for determining methionine and cysteine bioavailability is that not all dietary methionine and cysteine is digested and absorbed from the small intestine. Selected methods designed to determine the extent of digestion and absorption are discussed. Finally, a concept for a new assay for determining methionine bioavailability, which includes determining the digestibility of methionine and methionine sulfoxide as well as the utilization of methionine sulfoxide, is presented.

Determination of Sulfur Amino Acids and Tryptophan in Foods and Food and Feed Ingredients: Collaborative Study

1988 ◽  
Vol 71 (3) ◽  
pp. 603-606
Author(s):  
Maryann C Allred ◽  
John L Macdonald
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Collaborative Study ◽  
Performic Acid ◽  
Cysteic Acid ◽  
Protein Hydrolysis ◽  
Sulfur Amino Acids ◽  
Feed Ingredients ◽  
Food And Feed

Abstract Samples of 4 foods, 1 animal feed, isolated soy protein, and 0-lao toglobulin were analyzed by 9 laboratories to determine concentrations of cysteine as cysteic acid, methionine as methionine sulfone, and tryptophan. Sulfur amino acids were determined by AOAC method 43.A08-43.A13 for food and feed ingredients, in which samples are oxidized with performic acid before protein hydrolysis with 6N HC1. Tryptophan was determined after protein hydrolysis with 4.2N NaOH. In both methods, free amino acids were separated by ionexchange or reverse-phase chromatography. Each laboratory was provided with detailed methods and with sealed vials containing solutions of standards. Samples were analyzed in duplicate, and variation between laboratories was determined. Coefficients of variation between laboratories for the 6 samples ranged from 5.50 to 11.8% for methionine as methionine sulfoxide, 8.59 to 17.3% for cysteine as cysteic acid, and 3.87 to 16.1% for tryptophan. Amino acid recoveries were determined by analysis of β-lactoglobulin and were based on expected levels of each amino acid obtained from amino acid sequence data. The mean recovery of cysteine was 97% with a range of 88-119%. For methionine, mean recovery was 98% (range 89-115%) and for tryptophan, 85% (range 59-102%). Method 43.A08- 43.A13 for food and feed ingredients has been adopted official first action for determination of cysteine and methionine in processed foods. The alkaline hydrolysis method has been adopted official first action for determination of tryptophan in foods and food and feed ingredients

Oxidation and Hydrolysis Determination of Sulfur Amino Acids in Food and Feed Ingredients: Collaborative Study

1985 ◽  
Vol 68 (5) ◽  
pp. 826-829 ◽  
Author(s):  
John L Macdonald ◽  
Mark W Krueger ◽  
John H Keller
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Performic Acid ◽  
Cysteic Acid ◽  
Feed Ingredients ◽  
Methionine Sulfone ◽  
Coefficients Of Variation ◽  
Food And Feed ◽  
The Mean

Abstract Samples of 6 food and feed ingredients and a purified protein, plactoglobulin, were analyzed by 7 laboratories to determine the concentrations of cysteine as cysteic acid and methionine as methionine sulfone. Samples were oxidized by reaction with performic acid before hydrolysis with 6N HC1. The free amino acids were then separated and measured by ion-exchange chromatography on dedicated amino acid analyzers. Each laboratory was provided with a detailed method as well as sealed vials containing solutions of standards. For the determination of cysteine as cysteic acid, the coefficients of variation between laboratories for duplicate samples ranged from 7.13 to 10.8% for the 6 ingredients. For the determination of methionine as methionine sulfone, the coefficients of variation between laboratories for duplicate samples ranged from 1.18 to 12.8% for the 6 ingredients. Cysteine and methionine recoveries were determined by analysis of β-Iactoglobulin and were based on expected levels of each amino acid from amino acid sequence data. The mean recovery of cysteine was 95% with a range of 91-101%. The mean recovery of methionine was 101% with a range of 98-106%. This method has been adopted official first action.

scholarly journals Thiol and disulphide contents of hen ovalbumin. C-Terminal sequence and location of disulphide bond

1970 ◽  
Vol 116 (4) ◽  
pp. 555-561 ◽  
Author(s):  
L. A. Fothergill ◽  
J. E. Fothergill
Keyword(s):  
Acetic Acid ◽  
Iodoacetic Acid ◽  
Disulphide Bond ◽  
Performic Acid ◽  
Cysteic Acid ◽  
Acid Oxidation ◽  
Double Labelling ◽  
Thiol Groups ◽  
Terminal Sequence

1. The thiol and disulphide contents of hen ovalbumin were investigated by p-chloromercuribenzoate titration, by determination of cysteic acid content after performic acid oxidation, by measurement of uptake of radioactive iodoacetic acid, and by assay of S-aminoethylcysteine after reaction with ethyleneimine. All results showed that ovalbumin had 6 half-cystine residues. Experiments with and without reducing agents demonstrated that there were 4 thiol groups and 1 disulphide bond. 2. A peptide containing equimolar amounts of S-carboxymethyl-cysteine, serine, valine and proline, but no lysine or arginine, was obtained by radioactive labelling of the cysteine residues with iodo[14C]acetic acid followed by electrophoretic and chromatographic separation of tryptic digests. It was concluded that the C-terminal sequence of ovalbumin is -Cys-Val-Ser-Pro. 3. The location of the disulphide bond was studied by using a double-labelling technique. It was shown that one end of the disulphide was located in this C-terminal peptide.

Quantitative Analysis of Cystine, Methionine, Lysine, and Nine Other Amino Acids by a Single Oxidation-4 Hour Hydrolysis Method

1987 ◽  
Vol 70 (1) ◽  
pp. 171-174 ◽  
Author(s):  
Charles W Gehrke ◽  
Paul R Rexroad ◽  
Robert M Schisla ◽  
Joseph S Absheer ◽  
Robert W Zumwalt
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Content ◽  
Performic Acid ◽  
Acid Oxidation ◽  
Hydrolysis Method ◽  
Methionine Sulfone ◽  
Limiting Amino Acid ◽  
Hydrolysis Of

Abstract The sulfur-containing amino acids cystine and methionine play important roles in animal, especially avian, nutrition. Because these ndror-containing amino acids are destroyed to varying extents by 6N HC1 hydrolysis, oxidation and hydrolysis of cystine to cysteic add and methionine to methionine sulfone have been widely used for determination of cystine and methionine. Lysine is considered the next limiting amino acid after the sulfur amino acids in poultry •ntrition; therefore, determination of the amino acid content of rations focuses first on these 3 amino acids. The objective of this investigation was to establish whether lysine and other amino acids could be accurately determined in proteinaceous materials which had mdergone performic acid oxidation. To perform this evaluation, lysine was determined in a variety of protein-containing materials both with and without performic acid oxidation. Performic acid oxidation followed by 6N HC1 hydrolysis at 145°C for 4 h allows accurate measurement of 3 amino acids especially important to poultry nutrition, cystine, methionine, and lysine, in a single preoxidized hydralysate; this method can be extended to another 9 protein amino adds.

Ozonolysis of unsaturated fatty acids. II. Esterification of the total products from the oxidative decomposition of ozonides with 2,2-dimethoxypropane

1967 ◽  
Vol 45 (13) ◽  
pp. 1405-1410 ◽  
Author(s):  
John D. Castell ◽  
R. G. Ackman
Keyword(s):  
Fatty Acids ◽  
Liquid Chromatography ◽  
Unsaturated Fatty Acids ◽  
Performic Acid ◽  
Acid Oxidation ◽  
Gas Liquid Chromatography ◽  
Positional Isomers ◽  
Flame Ionization ◽  
Hydrogen Flame

The total acidic products from the performic acid oxidation of the ozonide of methyl oleate formed in methanol may be esterified directly in a few hours with 2,2-dimethoxypropane. The ester concentrations are adequate for the determination of the positional isomers of monoethylenic fatty acids directly from the reaction mixture, using a hydrogen flame ionization gas–liquid chromatography detector. Dimethyl sulfoxide was not required to prevent the breakdown of 2,2-dimethoxypropane under the conditions employed.

Recent Advances in the Chemistry of Covalently Bound Flavin Coenzymes

1972 ◽  
Vol 27 (9) ◽  
pp. 1069-1071 ◽  
Author(s):  
W. C. Kenney ◽  
W. H. Walker ◽  
E. B. Kearney ◽  
R. Seng ◽  
T. P. Singer ◽  
...  
Keyword(s):  
Amino Acid ◽  
Absorption Band ◽  
Performic Acid ◽  
Cysteic Acid ◽  
Hypsochromic Shift ◽  
Ninhydrin Reaction ◽  
Acid Environment ◽  
Definite Proof ◽  
Covalently Bound

Following elucidation of the structures of the flavin components of succinate dehydrogenase (SD) as N (3) -histidyl-8α-FAD and of monoamine oxidase (MAO) as cysteinyl-8α-FAD and determination of the peptide sequences around the flavin sites of these enzymes, attention has been focused on the covalently bound FAD of Chromatium cytochrome c-552. As documented in preliminary communications, the FAD moiety of this enzyme is also substituted at the 8α-position, as judged from ESR hyderfine structure of the free radical cation and the characteristic hypsochromic shift of the second absorption band of the neutral flavoquinone in purified preparations of the flavin. Definite proof has come from the liberation of 8-carbxyriboflavin on performic acid treatment of the enzyme. In regard to ESR and optical spectra and the tendency of the purified flavin (liberated by proteolysis) to undergo autooxidation with a further hypsochromic shift of the second absorption band and increased fluorescence, the flavin resembles the MAO flavin. The fact that fluorescence is >90% quenched at all pH values even at the FMN level and doees not vary with pH between 3.2 and 8 also suggests a thioether linkage as in cysteinyl riboflavin. In many respects, however, the Chromatium flavin differs from cysteinyl riboflavin. Highly purified preparations from tryptic-chymotryptic digests give a positive chloroplatinic test. Electrophoresis clearly shows the presence of carboxyl and amino groups but the peptide gives no characteristic ninhydrin reaction and amino acid analysis of performic acid oxidized samples yields cysteic acid and threonine in amounts less than equimolar to the flavin. The amino acid environment around the flavin may account for these results although a linkage other than a thioether remains a possibility.

The Histochemical Demonstration of Keratin by Methods involving Selective Oxidation

1951 ◽  
Vol s3-92 (20) ◽  
pp. 393-402
Author(s):  
A. G. EVERSON PEARSE
Keyword(s):  
Periodic Acid ◽  
Cobalt Nitrate ◽  
Histochemical Demonstration ◽  
Performic Acid ◽  
Cysteic Acid ◽  
Acid Oxidation ◽  
Reaction Products ◽  
Periodic Acid Schiff ◽  
Periodic Acid Oxidation ◽  
Schiff Reaction

1. Oxidation of tissues with performic acid gives rise to histochemically detectable reaction products particularly in two classes of material. These are keratin and lipoids of the phosphatide class. 2. Three methods have been evolved for visualizing the effect of performic acid on cystine-containing structures; two of these (performic acid/Schiff and perfoiTnic acid/cobalt nitrate) also record the effect on lipoids. 3. An attempt has been made to elucidate the chemistry of the reactions and it is suggested that oxidation of cystine in the tissues gives rise not only to cysteic acid (alanine-beta-sulphonic) but to another acid (alanine-beta-sulphinic). The latter is responsible for the positive reaction with Schiff's solution. 4. The Schiff reaction with performic acid oxidized lipoids is due to the formation of substances giving the reactions of aldehydes. It is possible that similar groups may be produced from lipoid molecules by periodic acid oxidation and that these and not polysaccharides (1.2 glycols) are responsible for the periodic acid-Schiff reaction in such cases.

Amino Acid Sequence Studies of Horseradish Peroxidase. I. Tryptic Peptides

1972 ◽  
Vol 50 (1) ◽  
pp. 44-62 ◽  
Author(s):  
K. G. Welinder ◽  
L. B. Smillie ◽  
G. R. Schonbaum
Keyword(s):  
Amino Acid ◽  
Horseradish Peroxidase ◽  
Amino Acid Sequence ◽  
Paper Electrophoresis ◽  
Iodoacetic Acid ◽  
Performic Acid ◽  
Cysteic Acid ◽  
Acid Oxidation ◽  
Tryptic Peptides ◽  
Tryptic Digest

Commercially available horseradish peroxidase (RZ 3.1) was characterized with respect to its homogeneity by (1) chromatography on CM-cellulose, (2) disc gel electrophoresis in alkaline and acidic buffers, (3) micro-scale sucrose gradient isoelectrofocusing in pH 3–10 and pH 8–10 gradients, (4) gel isoelectrofocusing in pH 3–10 and pH 8–10 gradients, and (5) amino acid and hexosamine analyses. The preparation was found to be highly homogeneous except by pH 8–10 gel isoelectrofocusing which resolved it into several very close bands. This heterogeneity has been assumed to reflect differences in carbohydrate composition rather than in the amino acid sequence or composition. Amino acid analyses after performic acid oxidation yielded eight cysteic acid residues per mole of enzyme. Since no S-carboxymethylcysteine was recovered after treatment of the protein in 8 M urea with iodoacetic acid, it was concluded that the enzyme has four disulfide bridges. Peptides resulting from a tryptic digest of the heme-free enzyme were purified by high-voltage paper electrophoresis and subjected to sequence analysis. Several half-cystine sequences were elucidated after isolation of the radioactive peptides from a tryptic digest of the reduced and 14C-S-carboxymethylated protein. The complete sequences of 21 and partial sequences of three tryptic peptides were determined. These account for 203 of the approximately 300 amino acid residues of this protein. Several sites of carbohydrate attachment were observed.

scholarly journals DNA Synthesis in Relation to Hyphal Branching and Wall Composition in Allomyces macrogynus

1985 ◽  
Vol 38 (1) ◽  
pp. 67 ◽  
Author(s):  
Jean Youatt
Keyword(s):  
Dna Synthesis ◽  
Sodium Sulfide ◽  
Methionine Sulfoxide ◽  
Cylindrical Shape ◽  
Sulfur Amino Acids ◽  
Hyphal Branching ◽  
The Third ◽  
Methionine Sulfone ◽  
Allomyces Macrogynus ◽  
Hyphal Tip

In A. macrogynus the first replication of DNA occurred after germination, at the time of the first branching of rhizoids. Before the second replication galactan in the wall exceeded the glucan content and was not firmly attached. After the second DNA replication hyphallengthening commenced with an increase in the content of glucan but the walls lacked rigidity. At the time of the third replication walls underwent a change which commenced at the hyphal tip and worked back to the rhizoids, converting the hyphae to a rigid, cylindrical shape. Branching commenced after the fourth replication of DNA. Multiple branching occurred when mature plants were transferred to glucose-histidine-methionine solution without further DNA synthesis. Hyphal branching was used to show that A. macrogynus was able to use methionine, methionine sulfoxide, methionine sulfone, sodium sulfide, cysteine, cystathionine and homocysteine but not cystine. Thioacetamide supported growth through many subcultures showing that A. macrogynus can synthesize its sulfur amino acids.

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