Electrophoresis in gels containing zwitterionic groups

Abstract

Yaron and Sober [ 11 have demonstrated that resolution in the electrophoretic separation of negatively charged oligoglutamates is improved by incorporating positively charged diethylaminoethyl (DEAE) groups into paper, and that incorporation of negatively charged carboxymethyl (CM) groups correspondingly improves resolution of oligolysines. One would expect an analogous improvement of resolution of proteins by introducing charges into separation matrices, but only if the charge densities of matrix and separated species were matched. This notion of "matching" is derived from protein chromatography on charged matrices, which shows that a relatively high charge density (e. g. of Dowex 2) is incompatible with protein adsorption, whereas a lower charge density (e. g. on DEAE), presumably corresponding to that on the protein surface, does allow charge interaction with the protein and therefore adsorption.The application of charged gels to electrophoresis has been described by Raymond and Nakamichi 121. They copolymerized either acrylic acid or methacrylylcholine methyl sulfate with Bis-crosslinked polyacrylamide to prepare either negatively or positively charged gels respectively. However, the introduction of charged groups into polyacrylamide gels affected only migration rates of proteins but not their resolution from one another. These effects were interpreted solely as a consequence of electroendosmosis, caused by the introduction of net charge into the matrix. Furthermore, the introduction of net charge into the gel led to distortion of the gel structure during electrophoresis. To overcome this disruption of gel structure, Ornstein (personal

Synthesis of Porous Zwitterionic Sulfobetaine Monoliths and Characterization of Their Interaction with Proteins

“…What most of these studies are aiming at is investigating the competition of inorganic salts and small organic molecules with solution phase self-interactions of zwitterionic polymers of high and balanced charge density, using polysulfoalkylbetaines as model polymers. It is therefore curious why no attempts have been made to extend these interactions to amphoteric biological macromolecules, thereby exploiting the chromatographic potential inherent in the ability of controlling the interactions between antipolyelectrolytic zwitterionomers and biological macromolecules . In this study we present the first findings of our investigations of porous monolithic sulfoalkylbetaine polymers, demonstrating that interactions between proteins and these polymers pave the way for a new mode of separating biomacromolecules using fully aqueous buffers.…”

Fiber type-specific analysis of AMPK isoforms in human skeletal muscle: advancement in methods via capillary nanoimmunoassay

“…Other proteins can exhibit APP MW shifts of 10 kDa or more between WB and CNIA, as observed with the scaffolding isoforms ␤ 1 and ␤ 2 . APP MW can be altered by several factors including protein-specific posttranslational modifications (40,41), the particular cell system used for protein expression, the formulation of the gel used for protein separation (15,16,37), and the particular ladder used to resolve the MW of the detected target. Thus MW shifts observed with CNIA (which uses a different separation matrix from that of WB) are reasonable and in accordance with effects seen in other gel separation methods.…”

Capillary gel electrophoresis

“…Polyacryloylmopholine [60] might be useful in capillary gel electrophoresis, although in classical gel electrophoresis, it has not been widely used. Gels containing zwitterionic groups, because of strong interactions between gel and, e.g., proteins [61], can be used in some special separations only; their general use, however, is not very likely.…”