Search results for " Ion Exchange"
showing 10 items of 65 documents
Specificity of deoxyribonuclease hydrolysis determined by high-performance liquid anion-exchange chromatography
1980
Protein mapping by two-dimensional high performance liquid chromatography.
2000
Current developments in drug discovery in the pharmaceutical industry require highly efficient analytical systems for protein mapping providing high resolution, robustness, sensitivity, reproducibility and a high throughput of samples. The potential of two-dimensional (2D) HPLC as a complementary method to 2D-gel electrophoresis is investigated, especially in view of speed and repeatability. The method will be applied for proteins of a molecular mass <20 000 which are not well resolved in 2D-gel electrophoresis. The 2D-HPLC system described in this work consisted of anion- or cation-exchange chromatography in the first dimension and reversed-phase chromatography in the second dimension. We …
The biological activity of bacteriophage DNA, prepared by the cationic detergent dilution technique
1975
Abstract The preparation of phage lambda DNA infecting E. coli K 12 with cationic detergent is described. This DNA infects E. coli spheroblasts with the same efficiency as DNA prepared by phenol methods.
Modelling and characterization of electrodialysis systems for multi-ionic solutions
2019
In this work a simplified approach related to membrane properties is required
Coupling CFD with a one-dimensional model to predict the performance of reverse electrodialysis stacks
2017
Abstract Different computer-based simulation models, able to predict the performance of Reverse ElectroDialysis (RED) systems, are currently used to investigate the potentials of alternative designs, to orient experimental activities and to design/optimize prototypes. The simulation approach described here combines a one-dimensional modelling of a RED stack with a fully three-dimensional finite volume modelling of the electrolyte channels, either planar or equipped with different spacers or profiled membranes. An advanced three-dimensional code was used to provide correlations for the friction coefficient (based on 3-D solutions of the continuity and Navier-Stokes equations) and the Sherwoo…
Interaction between N-terminal domain of H4 and DNA is regulated by the acetylation degree.
1998
Abstract To study whether the acetylation of one or more of the four acetylatable lysines of histone H4 affects its binding to DNA, we have designed a protection experiment with a model system consisting in phage lambda DNA as substrate, Stu I as restriction endonuclease and histone H4 with different degrees of acetylation as the protective agent. It can be deduced from the experimental data that the protection afforded by the histone is not dependent on the number of positive charges lost by acetylation. Thus, non-acetylated H4 and mono-acetylated H4 cause similar protection, while di-acetylation of the histone seems to be the crucial step in significantly weakening the interaction between…
Liquid chromatographic determination of toxigenic secondary metabolites produced by Fusarium strains.
2002
Various liquid chromatographic methods used in the analysis of mycotoxins (zearalenone, trichothecenes and fumonisins) produced by Fusarium species were compared in this work. The results demonstrate the suitability of modern clean-up procedures employing multifunctional MycoSep and immunoaffinity columns although these methods are more expensive than conventional methodologies for clean-up. HPLC with both fluorescence and photodiode array detection is a suitable technique for the analysis of toxic secondary metabolites produced by Fusarium species; different derivatisation strategies have been studied to improve the sensitivity of the technique because of the low concentration of these met…
Killer toxin of Hanseniaspora uvarum
1990
The yeast Hanseniaspora uvarum liberates a killer toxin lethal to sensitive strains of the species Saccharomyces cerevisiae. Secretion of this killer toxin was inhibited by tunicamycin, an inhibitor of N-glycosylation, although the mature killer protein did not show any detectable carbohydrate structures. Culture supernatants of the killer strain were concentrated by ultrafiltration and the extracellular killer toxin was precipitated with ethanol and purified by ion exchange chromatography. SDS-PAGE of the electrophoretically homogenous killer protein indicated an apparent molecular mass of 18,000. Additional investigations of the primary toxin binding sites within the cell wall of sensitiv…
Molecular dynamics simulations of elementary chemical processes in liquid water using combined density functional and molecular mechanics potentials.…
1997
The first molecular dynamics (MD) simulation of a chemical process in solution with an ab initio description of the reactant species and a classical representation of the solvent is presented. We study the dynamics of proton (deuterium) transfer in strongly hydrogen-bonded systems characterized by an energy surface presenting a double well separated by a low activation barrier. We have chosen the hydroxyl-water complex in liquid water to analyze the coupling between the reactive system and the environment. The proton is transferred from one well to the other with a frequency close to 1 ps−1 which is comparable to the low-frequency band associated to hindered translations, diffusional transl…
Ion-exchange high-performance liquid chromatography of nucleotides and polypeptides on new types of ion-exchange sorbents, based on polystyrene-coate…
1991
A novel type of ion exchanger was prepared by multipoint covalent binding of polystyrene chains onto the surface of porous silica followed by polymer-analogous modification of the bonded layer. Both anion and cation exchangers were synthesized and examined in the separation of nucleotides and proteins. Rapid and efficient separation of basic polypeptides on strong anion exchangers and that of acidic polypeptides on strong cation exchangers could be achieved. For the separation of complete mixtures of polypeptides the application of zwitter-ionic ion exchangers can be recommended.