Gold(III)-Induced Oxidation of Amino Acids and Malonic Acid: Reaction Pathways Studied by NMR Spectroscopy with Isotope Labelling

2002 ◽  
Vol 49 (4) ◽  
pp. 499-504 ◽  
Author(s):  
Juan Zou ◽  
John A. Parkinson ◽  
Peter J. Sadler
Keyword(s):  
Amino Acids ◽  
Nmr Spectroscopy ◽  
Malonic Acid ◽  
Reaction Pathways ◽  
Isotope Labelling ◽  
Acid Reaction

31P NMR Spectroscopy as a Powerful Tool for the Determination of Enantiomeric Excess and Absolute Configurations of α-Amino Acids

2003 ◽  
Vol 42 (4) ◽  
pp. 1006-1013 ◽  
Author(s):  
Judith Bravo ◽  
Carlos Cativiela ◽  
Julio E. Chaves ◽  
Rafael Navarro ◽  
Esteban P. Urriolabeitia
Keyword(s):  
Amino Acids ◽  
Nmr Spectroscopy ◽  
31P Nmr ◽  
Enantiomeric Excess ◽  
31P Nmr Spectroscopy

Discrimination of Enantiomers of Amides with Two Stereogenic Centers Enabled by Chiral Bisthiourea Derivatives Using 1H NMR Spectroscopy

2021 ◽  
Author(s):  
Hanchang Zhang ◽  
Hongmei Zhao ◽  
Jie Wen ◽  
Zhanbin Zhang ◽  
Pericles Stavropoulos ◽  
...  
Keyword(s):  
Amino Acids ◽  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Chiral Recognition ◽  
Stereogenic Centers

Enantiomers of a few new amides containing two stereogenic centers have been derived from D- and L-α-amino acids as guests for chiral recognition by 1H NMR spectroscopy. A variety of...

scholarly journals Comparison of Physicochemical Properties and Metabolite Profiling Using 1H NMR Spectroscopy of Korean Wheat Malt

Foods ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1436
Author(s):  
Yang Soo Byeon ◽  
Dabeen Lee ◽  
Young-Shick Hong ◽  
Seung-Taik Lim ◽  
Sang Sook Kim ◽  
...  
Keyword(s):  
Amino Acids ◽  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Enzyme Activities ◽  
Metabolite Profiling ◽  
1H Nmr Spectroscopy ◽  
Wheat Varieties ◽  
1H Nuclear Magnetic Resonance ◽  
The Us ◽  
Metabolic Properties

The objective of this study was to compare the physicochemical, enzymatic, and metabolic properties of two control wheat malts imported from Germany and the US to those of malts made from three Korean wheat varieties: Triticumaestivum L., var. Anzunbaengi, Jokyung, and Keumkang. The qualities and enzyme activities of the Korean wheat malts were generally similar to those of the control wheat malts. The Korean wheat malts had slightly lower diastatic power and enzyme activities related to saccharification. The analysis of metabolites in the wheat malt samples was performed using 1H nuclear magnetic resonance (NMR) metabolomics, which identified 32 metabolites that differed significantly among the samples. Most amino acids and lipids were more abundant in the Korean wheat malts than in the control wheat malts. These differences among malts could influence the quality and flavor of wheat beers. Further brewing studies are necessary to identify the association between beer quality and individual malt metabolites.

X-ray studies on crystalline complexes involving amino acids and peptides. XL. Conformational variability, recurring and new features of aggregation, and effect of chirality in the malonic acid complexes of DL- and L-arginine

2002 ◽  
Vol 58 (6) ◽  
pp. 1051-1056 ◽  
Author(s):  
N. T. Saraswathi ◽  
M. Vijayan
Keyword(s):  
Amino Acids ◽  
Hydrogen Bonding ◽  
Amino Acid ◽  
Crystal Structures ◽  
Malonic Acid ◽  
Conformational Flexibility ◽  
X Ray ◽  
Conformational Variability ◽  
Aggregation Pattern ◽  
Positively Charged

The crystal structures of the complexes of malonic acid with DL- and L-arginine, which contain positively charged argininium ions and negatively charged semimalonate ions, further demonstrate the conformational flexibility of amino acids. A larger proportion of folded conformations than would be expected on the basis of steric consideration appears to occur in arginine, presumably because of the requirements of hydrogen bonding. The aggregation pattern in the DL-arginine complex bears varying degrees of resemblance to patterns observed in other similar structures. An antiparallel hydrogen-bonded dimeric arrangement of arginine, and to a lesser extent lysine, is a recurring motif. Similarities also exist among the structures in the interactions with this motif and its assembly into larger features of aggregation. However, the aggregation pattern observed in the L-arginine complex differs from any observed so far, which demonstrates that all the general patterns of amino-acid aggregation have not yet been elucidated. The two complexes represent cases where the reversal of the chirality of half the amino-acid molecules leads to a fundamentally different aggregation pattern.

THE WEIGHT-DEPRESSING ACTION OF α-METHYL-DL-TRYPTOPHAN IN THE RAT

1962 ◽  
Vol 40 (1) ◽  
pp. 739-747 ◽  
Author(s):  
I. Sankoff ◽  
T. L. Sourkes
Keyword(s):  
Amino Acids ◽  
Body Weight ◽  
Glyoxylic Acid ◽  
Essential Amino Acids ◽  
Enzymic Activity ◽  
B Vitamins ◽  
Metabolic Studies ◽  
Comparable Effect ◽  
Acid Reaction ◽  
Tryptophan Pyrrolase

α-Methyl-DL-tryptophan, injected intraperitoneally into rats, has a weight-depressing action lasting up to 72 hours. Dosages in the range 0.015–2.0 millimoles/kg body weight (3.3–436 mg/kg) are effective. Attempts to antagonize the weight-depressing action by giving essential amino acids and B vitamins were unsuccessful. Metabolic studies have shown that about half the injected dose of the compound (or its derivatives), as measured by the Hopkins–Cole glyoxylic acid reaction, is excreted in the urine in 24 hours; most of this appears during the first 4 hours after the injection. Ina search for an explanation for the weight-depressing action of α-methyltryptophan, tryptophan pyrrolase activity in the liver was estimated. This enzymic activity increases for 8 hours after the injection of α-methyltryptophan, and thereafter remains high for 72 hours. Tryptophan-injected animals showed increases in tryptophan pyrrolase level for 1.5 hours, and a return to normal concentrations within 24 hours. Other α-methyl amino acids which were tested had no comparable effect on body weight.

scholarly journals HISTOCHEMICAL DIFFERENTIATION BETWEEN TYROSINE AND CHLOROGENIC ACID IN PLANT TISSUES I. NITROUS ACID REACTIONS AND METAL CHELATION OF NITROSOTYROSINE

1968 ◽  
Vol 16 (3) ◽  
pp. 191-198 ◽  
Author(s):  
R. M. REEVE
Keyword(s):  
Amino Acids ◽  
Chlorogenic Acid ◽  
Nitrous Acid ◽  
Metal Chelate ◽  
Ultrastructural Localization ◽  
Plant Tissues ◽  
Metal Chelation ◽  
Copper Chelation ◽  
Acid Reaction ◽  
Color Reactions

Copper chelation of nitrosotyrosine has been found useful for histochemical localization for tyrosine in thick, fresh sections of large celled plant tissues. The nitrous acid reaction for ortho-dihydroxyphenolics also has been found useful for localization of chlorogenic acid, caffeic acid and dihydroxyphenylalanine in plant tissues. Application of these tests separately to serially adjacent sections demonstrated the distribution of tyrosine and chlorogenic acid in different plant tissues. Tests tube reactions on known substances verified specificity and also demonstrated that the presence of other amino acids and phenolics did not interfere with the positive test for tyrosine. The color reactions are sufficiently intense for stereoscopic microscopy and tested sections may be measured photometrically. Further adaptability of the nitrosotyrosine-metal chelate reaction to procedures for ultrastructural localization is suggested.

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