Comparisons of 17 lots of 2-oxoglutarate, and specifications for use of this substrate in reference methods.

1985 ◽  
Vol 31 (6) ◽  
pp. 812-818
Author(s):  
P N Bowers ◽  
G N Bowers ◽  
R B McComb
Keyword(s):  
Catalytic Activity ◽  
Liquid Chromatography ◽  
Glutamate Dehydrogenase ◽  
Spectral Characteristics ◽  
Poor Quality ◽  
Activity Concentrations ◽  
Reference Methods ◽  
Specific Analysis ◽  
Quality Material ◽  
Salt Forms

Abstract We examined 17 lots of 2-oxoglutarate (seven acid forms, three K salt forms, and seven Na salt forms), obtained from eight commercial suppliers, for suitability for measuring aspartate aminotransferase (EC 2.6.1.1) and alanine aminotransferase (EC 2.6.1.2) in human serum. Measurements of the catalytic activity concentrations of these two aminotransferases with each of these 17 preparations were not sufficiently sensitive to distinguish good from poor-quality material. Thus, we ranked these lots for purity, by specific analysis with glutamate dehydrogenase and by liquid chromatography, and determined the water content, acid content, and spectral characteristics of each. On the basis of a 2-oxoglutarate assay value by glutamate dehydrogenase of 98% or greater, we considered seven of the preparations acceptable and 10 unacceptable. The molar absorptivities (L X mol-1 X cm-1, mean +/- SD) of the seven acceptable lots in 1 mol/L HCl were: epsilon 325 nm = 9.12 +/- 0.02 (CV = 0.2%), epsilon 279 nm = 2.63 +/- 0.23 (CV = 9.9%), and epsilon 245 nm = 37.9 +/- 4.1 (CV = 10.9%). Use of these spectrophotometric limits alone unambiguously distinguished the inferior lots of 2-oxoglutarate. We urge the inclusion of detailed spectrophotometric specifications for 2-oxoglutarate in Reference Methods for aminotransferase measurements.

scholarly journals Identification of phenolic compounds of dry extract of dandelion herb and large burdock leaf tea

2019 ◽  
Vol 18 (2) ◽  
pp. 73-77
Author(s):  
L. M. Fedoseeva ◽  
Yu. I. Chistova
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Phenolic Compounds ◽  
High Performance ◽  
Uv Light ◽  
Spectral Characteristics ◽  
Water System ◽  
Dry Extract ◽  
Caffeic Acid Derivatives ◽  
Layer Chromatography

The purpose of this work is to study of phenolic compounds in the dry extract of dandelion herb and large burdock leaf tea.Materials and methods . The separation and identification of phenolic compounds of dry extract of dandelion herb and large burdock leaf tea by thin-layer chromatography and high-performance liquid chromatography with UV-detectionhas been carried out.Results . As a result of research, it has been established that during TLC the optimal system for the separation of phenolic compounds is the ethyl acetate – formic acid – water system (10:2:3). On the chromatogram four spots were found corresponding to the value of Rf and fluorescence in UV-light to flavonoids of the flavone group and phenolic acids (chlorogenic and caffeic acids). For further identification of phenolic compounds using HPLC, eight peaks were found, which in terms of retention time and spectral characteristics correspond to phenologlycosides, chlorogenic acid, caffeic acid derivatives, ferulic acid, umbelliferone.Conclusions . Thus, the dry extract of dandelion herb and large burdock leaf tea contains hydroxycinnamic acids and their derivatives, compounds of coumarin nature, phenologlycosides.

Influence of substrate concentration on the activation of transketolase, aspartate aminotransferase, and glutathione reductase by coenzymes.

1984 ◽  
Vol 30 (1) ◽  
pp. 143-144
Author(s):  
J C Hafkenscheid ◽  
C M van Dijk
Keyword(s):  
Catalytic Activity ◽  
Glutathione Reductase ◽  
Aspartate Aminotransferase ◽  
Substrate Concentration ◽  
Activity Concentrations ◽  
Influence Of Substrate ◽  
Underlying Mechanisms ◽  
Substrate Concentrations

Abstract We investigated the mechanism by which the three most commonly measured enzymes in erythrocytes are activated by their respective coenzymes by determining the catalytic activity concentrations of transketolase (EC 2.2.1.1), aspartate aminotransferase (EC 2.6.1.1), and glutathione reductase (EC 1.6.4.2) in relation to various substrate concentrations. We conclude that the underlying mechanisms by which the enzymes are activated are not the same.

Changes in mass and catalytic activity concentrations of aspartate aminotransferase isoenzymes in serum after a myocardial infarction.

1986 ◽  
Vol 32 (3) ◽  
pp. 496-500 ◽  
Author(s):  
A E Niblock ◽  
G Jablonsky ◽  
F Y Leung ◽  
A R Henderson
Keyword(s):  
Myocardial Infarction ◽  
Enzyme Activity ◽  
Catalytic Activity ◽  
Aspartate Aminotransferase ◽  
Left Ventricular ◽  
Peak Activity ◽  
Ventricular Failure ◽  
Total Enzyme Activity ◽  
Activity Concentrations ◽  
Total Enzyme

Abstract We used an RIA and inhibition of enzyme activity to monitor the changes in mass and catalytic concentrations of the aspartate aminotransferase (EC 2.6.1.1;AST) isoenzymes in serum after myocardial infarction. Cytosolic (c-AST) and mitochondrial (m-AST) forms of AST were present in sera from all 38 of our patients. Although the immunological and catalytic concentrations of both isoenzymes correlated well with the size of the infarct, c-AST gave a better measure than did m-AST. About 20% of the total enzyme activity at peak activity was from the mitochondrial isoenzyme. Both isoenzyme activities peak at very nearly the same time, but m-AST has the longer half-life. Immunological evidence of the mitochondrial isoenzyme can be detected in serum for at least eight days after the infarct. The presence of left ventricular failure produces greater serum isoenzyme activities than in those without failure.

The Shelves that Won't Hold: Material Politics and Social Inequality in Spatial Design Practice

Design Issues ◽  
2019 ◽  
Vol 35 (4) ◽  
pp. 61-68
Author(s):  
Mona Sloane
Keyword(s):  
Poor Quality ◽  
Design Practice ◽  
Power Struggle ◽  
Unequal Treatment ◽  
Vulnerable Communities ◽  
Community Theater ◽  
Spatial Design ◽  
Material Politics ◽  
Unequal Access ◽  
Quality Material

This article discusses how a material divide that leaves vulnerable communities with homes made of poor quality material is perpetuated in the system of spatial design. It examines a vignette about the development of the community theater in London to illustrate the unequal access to and participation in the design process as “intentional problem-solving” by different stakeholders. The discussion outlines how materiality can become the locus of public dispute and power struggle, as well as the key reference point for valuation frameworks and calculation practices. The article points out that material politics within spatial design practice play a central role in legitimizing unequal treatment within the material planning of space, and that individual designers can rarely challenge these structures themselves.

scholarly journals High-Performance Liquid Chromatography Analyses of Pyoverdin Siderophores Differentiate among Phytopathogenic Fluorescent Pseudomonas Species

2003 ◽  
Vol 69 (2) ◽  
pp. 1143-1153 ◽  
Author(s):  
Alain Bultreys ◽  
Isabelle Gheysen ◽  
Bernard Wathelet ◽  
Henri Maraite ◽  
Edmond de Hoffmann
Keyword(s):  
Amino Acids ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Pseudomonas Syringae ◽  
Related Species ◽  
High Performance ◽  
Spectral Characteristics ◽  
Iron Chelation ◽  
Chromatography Method ◽  
Pseudomonas Cichorii

ABSTRACT The relationship of pyoverdins produced by 41 pathovars of Pseudomonas syringae and by phytopathogenic Pseudomonas species was investigated. A high-performance liquid chromatography method for analyzing the culture medium proved to be superior to isoelectric focusing for detecting pyoverdin production, for differentiating slightly different pyoverdins, and for differentiating atypical from typical Fe(III)-chelated pyoverdins. Nonfluorescent strains were found in Pseudomonas amygdali, Pseudomonas meliae, Pseudomonas fuscovaginae, and P. syringae. Pseudomonas agarici and Pseudomonas marginalis produced typical pyoverdins. Among the arginine dihydrolase-negative fluorescent Pseudomonas species, spectral, amino acid, and mass spectrometry analyses underscored for the first time the clear similarities among the pyoverdins produced by related species. Within this group, the oxidase-negative species Pseudomonas viridiflava and Pseudomonas ficuserectae and the pathovars of P. syringae produced the same atypical pyoverdin, whereas the oxidase-positive species Pseudomonas cichorii produced a similar atypical pyoverdin that contained a glycine instead of a serine. The more distantly related species Pseudomonas asplenii and Pseudomonas fuscovaginae both produced a less similar atypical pyoverdin. The spectral characteristics of Fe(III)-chelated atypical pyoverdins at pH 7.0 were related to the presence of two β-hydroxyaspartic acids as iron ligands, whereas in typical pyoverdins one of the ligands is always ornithine based. The peptide chain influenced the chelation of iron more in atypical pyoverdins. Our results demonstrated that there is relative pyoverdin conservation in the amino acids involved in iron chelation and that there is faster evolution of the other amino acids, highlighting the usefulness of pyoverdins in systematics and in identification.

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