Immobiline-based two-dimensional gel electrophoresis: An optimised protocol for resolution of human colonic mucosal proteins

An optimised protocol for the production of two-dimensional protein patterns of human colonic mucosal cells using immobilised pH gradients in the first dimension is presented. We tested a wide variety of solubilising agents and electrophoretic parameters, separately and in combination. Protein solubilisation was found to be best using a lysis solution containing 9 M urea, 2% Triton X-100, 2% 2-mercaptoethanol, 0.8% Pharmalyte pH 3-10 and 8 mM phenylmethylsulfonyl fluoride (PMSF). Horizontal streaking of basic proteins in the first dimension was virtually eliminated by a combination of washing Immobiline strips in 100 mM ascorbic acid, pH 4.5, for 24 h before use and isoelectric focusing samples at 40°C. The presence of 2% glycerol in the first dimension resulted in tighter resolution throughout the entire pH range. The use of these conditions may prove to have broad applicability to the generation of optimally resolved Immobiline-based two-dimensional protein patterns of many other tissues.