Antioxidative Activity of (E)-2-Octenal/Amino Acids Reaction Products

1995 ◽  
Vol 43 (3) ◽  
pp. 795-800 ◽  
Author(s):  
Manuel Alaiz ◽  
Rosario Zamora ◽  
Francisco J. Hidalgo
Keyword(s):  
Amino Acids ◽  
Antioxidative Activity ◽  
Reaction Products

The Kinetics of Inhibition of the Action of Thrombin by the Fibrinopeptides Formed during the Clotting of Fibrinogen

1966 ◽  
Vol 16 (01/02) ◽  
pp. 277-295 ◽  
Author(s):  
A Silver ◽  
M Murray
Keyword(s):  
Amino Acids ◽  
Competitive Inhibition ◽  
Amorphous Material ◽  
Peptide Bond ◽  
Initial Reaction ◽  
Reaction Products ◽  
Coagulation Mechanism ◽  
Kinetics Of ◽  
Kinetics Of Inhibition ◽  
Burk Plot

SummaryVarious investigators have separated the coagulation products formed when fibrinogen is clotted with thrombin and identified fibrinopeptides A and B. Two other peaks are observed in the chromatogram of the products of coagulation, but these have mostly been dismissed by other workers. They have been identified by us as amino acids, smaller peptides and amorphous material (37). We have re-chromatographed these peaks and identified several amino acids. In a closed system of fibrinogen and thrombin, the only reaction products should be fibrin and peptide A and peptide B. This reasoning has come about because thrombin has been reported to be specific for the glycyl-arginyl peptide bond. It is suggested that thrombin also breaks other peptide linkages and the Peptide A and Peptide B are attacked by thrombin to yield proteolytic products. Thrombin is therefore probably not specific for the glycyl-arginyl bond but will react on other linkages as well.If the aforementioned is correct then the fibrinopeptides A and B would cause an inhibition with the coagulation mechanism itself. We have shown that an inhibition does occur. We suggest that there is an autoinhibition to the clotting mechanism that might be a control mechanism in the human body.The experiment was designed for coagulation to occur under controlled conditions of temperature and time. Purified reactants were used. We assembled an apparatus to record visually the speed of the initial reaction, the rate of the reaction, and the density of the final clot formed after a specific time.The figures we derived made available to us data whereby we could calculate and plot the information to show the mechanism and suggest that such an inhibition does exist and also further suggest that it might be competitive.In order to prove true competitive inhibition it is necessary to fulfill the criteria of the Lineweaver-Burk plot. This has been done. We have also satisfied other criteria of Dixon (29) and Bergman (31) that suggest true competitive inhibition.

Chemically Selective Reactions in Confined Spaces in Hybrid Aerogels

2005 ◽  
Vol 899 ◽  
Author(s):  
Xipeng Liu ◽  
Chunhua Yao ◽  
William M Risen
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Metal Ions ◽  
Chemical Reactions ◽  
Reaction Products ◽  
Spatial Confinement ◽  
Confined Spaces ◽  
Hybrid Silica ◽  
Hybrid Aerogels ◽  
Chemically Selective

AbstractBy employing novel hybrid silica/functional polymer aerogels, control of the course of chemical reactions between reactants confined inside of the aerogels with reactants whose access to the confinement domain is controlled by diffusion has been explored. Thus, monolithic silica/biopolymer hybrid aerogels have been synthesized with coordinated metal ions that can react with amino acids, such as L-cysteine, that are provided externally in a surrounding solution. Metal ions, such as Au(III), that can react in solution with the amino acid to produce one set of products under a given set of stoichiometric or concentration conditions, and a different set of products under a second set of conditions, were selected for incorporation into the aerogel. It was discovered that the course of the reaction can be changed by spatial confinement of the reaction domain in the aerogel. For example, in the case of Au(III) and L-cysteine, the Au(III) ions are confined in nanoscale domains, and when they are reacted with the amino acid, the nature of the reaction products is controlled by diffusion of the L-cysteine into the domains. Exploration of these and related phenomena will be presented.

scholarly journals Strecker degradation products of aspartic and glutamic acids and their amides

2013 ◽  
Vol 19 (No. 2) ◽  
pp. 41-45 ◽  
Author(s):  
J. Rössner ◽  
J. Velíšek ◽  
F. Pudil ◽  
J. Davídek
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Degradation Products ◽  
Dicarboxylic Acids ◽  
Reaction Products ◽  
Degradation Reactions ◽  
Strecker Aldehydes ◽  
Volatile Products ◽  
Acid Acid

Aspartic and glutamic acids, asparagine and glutamine were oxidised with either potassium peroxodisulphate or glyoxal. Nonvolatile products were derivatised and analysed by GC/FID and GC/MS. Volatile reaction products were isolated and analysed by the same methods. It was found that the degradation reactions of amino acids are complex. Amino acids are principally degraded via the corresponding a-keto acids to Strecker aldehydes (aspartic acid to oxalacetic and 3-oxopropionic acids and glutamic acid to a-ketoglutaric and 4-oxobutyric acids), which are unstable and decomposed by decarboxylation to the corresponding aldehydes. Aspartic acid also eliminates ammonia and yields fumaric acid whereas glutamic acid gives rise to an imine, pyroglutamic acid. A recombination of free radicals leads to dicarboxylic acids (succinic acid from aspartic acid, succinic, glutaric and adipic acids from glutamic acid). The major volatile products (besides the aldehydes) are lower carboxylic acids (acetic acid from aspartic acid and propionic acid acid from glutamic acid) that can at least partly arise by radical reactions. In both quality and quantity terms, a higher amount of degradation products arises by oxidation of amino acids by peroxodisulphate.

Antimutagenic Effect of Maillard Reaction Products Prepared from Glucose and Tryptophan

1992 ◽  
Vol 55 (8) ◽  
pp. 615-619 ◽  
Author(s):  
GOW-CHIN YEN ◽  
JEN-DAN LII
Keyword(s):  
Maillard Reaction ◽  
Antioxidative Activity ◽  
Reducing Power ◽  
Molar Ratio ◽  
Maillard Reaction Products ◽  
Alkaline Ph ◽  
Reaction Products ◽  
Reaction Conditions ◽  
Antimutagenic Effect ◽  
Effect Of Glucose

The antimutagenicity of Maillard reaction products (MRPs) prepared by refluxing D-glucose and L-tryptophan under various reaction conditions was determined by means of the Ames test. The dose of MRPs with 5 mg per plate showed no toxicity, and mutagenicity to Salmonella typhimurium TA98 and TA100 was used for antimutagenic assay. The mutagenicity of 2-amino-3-methylimidazo (4,5-f) quinoline (IQ) and 2-amino-6-methyldipyrido (1,2-a:3′,2′-d) imidazole (Glu-P-1) toward TA98 was markedly reduced by the addition of glucose-tryptophan MRPs, whereas the mutagenicity of 4-nitroquinoline-N-oxide (NQNO) was not inhibited. The mutagenicity of IQ, Glu-P-1, and NQNO toward TA100 was also markedly reduced by glucose-tryptophan MRPs, but the mutagenicity of NQNO was only slightly inhibited. Greater antimutagenic effects of glucose-tryptophan MRPs were found when these materials were prepared at an alkaline pH. The optimum combinations of reaction conditions for obtaining antimutagenic MRPs to IQ were glucose-tryptophan molar ratio = 0.5:0.25 at pH 9.0 for 5 and 10 h, molar ratio = 0.5:0.5 at pH 11.0 for 10 h, and molar ratio = 1.0:0.25 at pH 7.0 for 15 h and at pH 11.0 for 15 h. The antimutagenic effect of glucose-tryptophan MRPs to IQ and Glu-P-1 was well correlated with their browning intensity, reducing power, and antioxidative activity. The antimutagenicity of glucose-tryptophan MRPs might be due to both desmutagenic and bio-antimutagenic effects.

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