Preparative Electrophoresis and

Porath, J, Some Recent Developments in Preparative Electrophoresis and Gel Filtration, Metabolism 13, 1004, 1964. 

The N-linked pentasaccharide core Man3(GlcNAc)2 glycopeptide bearing the extracellular MMP inducer sequence 517 (emmprin 34—58) has been successfully linked to G(l) PAMAM aminodendrimer by thioester activation (Fig. 63). The resulting octameric 30 kDa construct was obtained in low yield, but was purified by preparative electrophoresis and fully characterized by MALDI-TOF mass spectrometry. The multivalent architecture was built to evaluate the requirement of emmprin multimerization for inducing MMP expression.384... 

Fully equipped protein purification laboratories should also have preparative electrophoresis and isoelectric focusing apparatuses for rare occasions when other techniques fail to give sufficient separation. 

It should also be mentioned that glycopeptides closely related to the pep-tido-polysaccharide of human-strain, wax D fractions are found in the culture filtrate of tubercle bacilli and in aqueous extracts thus, Kdra and Keil have described a glycopeptide, isolated from culture filtrates of virulent, human strains of M. tubercidosia, which could be purified by preparative electrophoresis and which contains alanine, a, -diaminopimelic acid, and glutamic acid in equimolecular proportions structure (22) was proposed for the peptide portion of this glycopeptide. 

Figure 15.14. Determination of peptide sequence using nanoelectrospray ionization, and a very high-resolution mass analyzer (Q-TOF). In the first quadrupole, a doubly charged peptide ion of m/z — 625.41 was selected and later fragmented. The m/z CID spectrum yields the FGDYGSIDYGR sequence, shown at the top.23 [Reprinted, with permission, from E. Gustafsson, K. Thoren, T. Larsson, P. Davidsson, K. Karlsson, and C. L. Nilsson, Identification of Proteins from Escherichia coli Using Two-Dimensional Semi-Preparative Electrophoresis and Mass Spectrometry. Rapid Communications in Mass Spectrometry 15, 2001, 428-432. Copyright 2001 John Wiley Sons, Ltd.]...

The PS I complexes of both species were purified, and low-molecular mass polypeptides were isolated from each by preparative electrophoresis and subjected to amino-terminal amino acid sequencing. Partial sequences were obtained for the psaC, psaD, psaE, and putative psaF gene products from Synechococcus sp. PCC 7002 partial sequences for the psaD and psaE gene products of Nos toe sp. PCC 8009 were also determined (19). The putative psaF product of Nostoe sp. was blocked. 

CE is generally more suited to analytical separations than to preparative-scale separations. However, given the success of CE methods for chiral separations, it seems reasonable to explore the utility of preparative electrophoretic methods to chiral separations. Thus, the purpose of this work is to highlight some of the developments in the application of preparative electrophoresis to chiral separations. Both batch and continuous processes will be examined. 

In considering the applicability of preparative classical electrophoretic methods to chiral separations, it should be noted that practitioners in the art of classical electrophoresis have been particularly inventive in designing novel separation strategies. For instance, pH, ionic strength and density gradients have all been used. Isoelectric focusing and isotachophoresis are well-established separation modes in classical electrophoresis and are also being implemented in CE separations [7, 8]. These trends are also reflected in the preparative electrophoretic approaches discussed here. 

The varions flavin phosphates and their acetyl derivatives were identified by pH titration, electrophoresis, and H-NMR, which permit direct analysis of crude reaction prodncts as well as rapid purity check of commercial flavin mononucleotide or riboflavin 5 -monophosphate (FMN or 5 -FMN) [7]. Riboflavin 4 -monophosphate was determined as the main by-product of commercial FMN by preparative TLC on cellulose with n-butanol/acetic add/water (5 2 3, v/v) as a solvent [7]. 

Chemical surface modifications The first surface modification for the purpose of eliminating EOF and protein adsorption was recommended by Hjerten.28 The attachment of vinyl silanes allowed the polymerization of a variety of molecules to the surface. Most of the chemical modifications used for preparing capillaries for electrophoresis originated from the experience acquired over the years preparing GC and LC stationary phases. Chemical modification should conform to certain requirements, including the prevention of adsorption, the provision of stable and constant EOF over a wide pH range, chemical stability, ease of preparation, and reproduciblity of preparation. The effects of silanization of the inner surface of capillaries on electrophoretic separations have been extensively studied.26-29... 

Kasicka, V., Pruslk, Z., Sazelova, P., Jiracek, J. and Barth, T., Theory of the correlation between capillary and free-flow zone electrophoresis and its use for the conversion of analytical capillary separations to continuous free-flow preparative processes. Application to analysis and preparation of fragments of insulin, ]. Chromatogr. A, 796, 211, 1998. 

R. M. C. Sutton and A. M. Stalcup. Preparative Electrophoresis. Encyclopedia of Separation Science, Academic Press Ltd (1999) in press. 

In the purification of pectinesterase from the fruits of Citrus nat-sudaidai,61 fractional salting-out with ammonium sulfate was followed by chromatography on a column of DEAE-cellulose and by separation of the active fraction on Sephadex G-100. A preparation (purified solution) having a specific activity 460-fold greater than that of the original extract was obtained. Its homogeneity was checked by disc electrophoresis, and its amino acid content was determined and fundamental, kinetic data were obtained. 

Preparative electrophoresis on Sephadex G-25 (Ref. 168) or double isoelectric focusing,208 preceded by chromatography on Sephadex G-75, CM-cellulose, and calcium phosphate, was used for the isolation of endo-D-galacturonanase from the filtrate of a Verticillium albo-atrum culture. The homogeneity was confirmed in both cases by electrophoresis on poly(acrylamide) gel. The molecular weight of the enzyme was close to the values found for Aspergillus endo-D-galacturonanases. 

Description of LC-MS, including free articles. This site has subdivisions such as proteomics, metabonomics, 2D-electrophoresis, and sample preparation. 

Jayle, Herman-Boussier, and Moretti have shown that different types of human Hp in amounts large enough for analysis can be prepared by fractional ammonium sulfate precipitation combined with a rather conventional, preparative electrophoresis in an acetate buffer of pH 5.8. Schultze and Heide (S2) utilize a more complicated procedure, in which preparative electrophoresis (acetate buffer, pH 4.4) is likewise the final step. 

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