Nonequilibrium pH Gel Electrophoresis (NEPHGE)

  • Mary F. Lopez
Part of the Springer Protocols Handbooks book series (SPH)


Nonequilibrium pH gel electrophoresis (NEPHGE) is a technique developed to resolve proteins with extremely basic isoelectric points (pH 7.5-11.0) (1,2). These proteins are difficult to resolve using standard IEF, because the presence of urea in IEF gels has a buffering effect and prevents the pH gradient from reaching the very basic values (with a pH above 7.3-7.6) (3). In addition, cathodic drift causes many very basic proteins to run off the end of the gel. During NEPHGE, proteins are not focused to their isoelectric point, but instead move at different rates across the gel owing to charge. For this reason, the accumulated volt hours actually determine the pattern spread across the gel. It is therefore imperative that volt hours be consistent to assure reproducible patterns.


Basic Protein Maximum Voltage Buffer Effect Reproducible Pattern Cathode Buffer 
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  1. 1.
    O’Farrell, P. Z., Goodman, H. M., and O’Farrell, P. H. (1977) High resolution two-dimensional electrophoresis of basic as well as acidic proteins. Cell 12, 1133–1142.PubMedCrossRefGoogle Scholar
  2. 2.
    Dunn, M. J. (1993) Isoelectric focusing, in Gel Electrophoresis: Proteins. Bios Scientific Publishers, Oxford, UK, pp. 65–85.Google Scholar

Copyright information

© Humana Press Inc., Totowa, NJ 2002

Authors and Affiliations

  • Mary F. Lopez
    • 1
  1. 1.Proteome SystemsWoburn

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