The current state of two-dimensional electrophoresis with immobilized pH gradients

The original protocol of two-dimensional electrophoresis with immobilized pH gradient (IPG-Dalt; Görg et al., Electrophoresis 1988, 9, 531—546) is updated. Merits and limits of different methods for sample solubilization, sample application (by cup-loading or in-gel rehydration) with respect to the pH interval used for IPG-isoelectric focusing are critically discussed. Guidelines for running conditions of analytical and micropreparative IPG-Dalt, using wide IPGs up to pH 12 for overview patterns, or narrow IPGs for zoom-in gels for optimum resolution and detection of minor components, are stated. Results with extended separation distances as well as automated procedures are demonstrated, and a comparison between protein detection by silver staining and fluorescent dyes is given. A brief trouble shooting guide is also included.