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Your search keyword '"S. SINDERN"' showing total 2 results
Start Over Author "S. SINDERN" Topic electrophoresis, polyacrylamide gel
2 results on '"S. SINDERN"'

1. The use of a hollow fiber membrane module in sample conditioning prior to electrophoresis.

Author

Schwarz T, Sindern S, Bartholmes P, and Kaufmann M

Subjects
Ammonium Sulfate, Animals, Capillary Action, Dialysis instrumentation, Dialysis methods, Electrophoresis, Polyacrylamide Gel methods, Euglena gracilis chemistry, Indicators and Reagents, Nitrosomonas chemistry, Polyethylene Glycols, Sodium Dodecyl Sulfate, Bacterial Proteins isolation & purification, Electrophoresis, Polyacrylamide Gel instrumentation, Protozoan Proteins isolation & purification
Abstract

A new method to continuously change the buffer conditions in samples prior to electrophoresis by counter-current dialysis has been developed using a hollow fiber membrane module (VariPerm M, bitop, Witten). It is demonstrated that the collected fractions of a column eluate after hydrophobic interaction chromatography cannot be analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) due to the high content of ammonium sulfate. In contrast, when the hollow fiber membrane module is used for on-line desalting of the eluate during chromatography, it is possible to detect distinct bands on SDS-gels even after sample concentration by evaporation. Moreover, adding polyethyleneglycol 20,000 to the counter-current dialysis buffer the hollow fiber membrane module is suitable for combined on-line sample desalting and sample concentration of living organisms during free flow electrophoresis (FFE): a culture of Nitrosomonas eutropha which could not significantly be detected by FFE without conditioning was successfully analyzed when concentrated and desalted on-line during sample application.

Published
1994
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2. Influence of .alpha.-Subunits on the High-Pressure Stability of Apo and Holo .beta.2-Subunits in the Bienzyme Complex Tryptophan Synthase from Escherichia coli

Author

S. Sindern, P. Bartholmes, and R. Van Eldik

Subjects
Macromolecular Substances, Hydrostatic pressure, Tryptophan synthase, medicine.disease_cause, Biochemistry, Dissociation (chemistry), Enzyme Reactivators, Enzyme Stability, Centrifugation, Density Gradient, Escherichia coli, Hydrostatic Pressure, Tryptophan Synthase, medicine, Trypsin, chemistry.chemical_classification, biology, Chemistry, Fluorescence, Dissociation constant, Kinetics, Crystallography, Spectrometry, Fluorescence, Enzyme, biology.protein, Electrophoresis, Polyacrylamide Gel, Spectrophotometry, Ultraviolet, Mathematics, Bar (unit)
Abstract

At a hydrostatic pressure of up to 2 kbar, the isolated alpha-subunit of tryptophan synthase from Escherichia coli proved to be a stable enzyme by virtue of specific activity as well as UV absorption and fluorescence emission spectra. The protein can therefore be regarded as a suitable effector for the investigation of structure-function relationships in the dimeric beta 2-subunit under the influence of high hydrostatic pressure. Complete deactivation of the beta 2-component in the alpha 2 beta 2 bienzyme complex occurs above 1300 bar (midpoint of transition for alpha apo beta 2, 790 bar; for alpha 2 holo beta 2, 1057 bar). Sucrose (13%) shifts both midpoints of transition to values higher by about 300 bar. As shown by sucrose gradient centrifugation and limited trypsinolysis, deactivation of the beta 2-dimer is paralleled by dissociation into denatured beta-chains. At 10 degrees C, the corresponding dissociation constants K at 1 bar as well as the reaction volumes of dissociation delta V are calculated as 4.2 x 10(-9) M and -196 mL/mol for the apo-beta 2-component and as 9.8 x 10(-19) M and -632 mL/mol for the holo-beta 2-component in the bienzyme complex. Furthermore, large negative activation volumes are determined, reflecting the rate increase with increasing pressure: -89 mL/mol for the apo-beta 2-dimer and -195 mL/mol for the holo-beta 2-dimer.(ABSTRACT TRUNCATED AT 250 WORDS)

Published
1995
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