Protein extraction from grape tissues by two-dimensional electrophoresis

At the onset of proteomic studies protein samples have to be accurately separated by two dimensional electrophoresis (2-DE); subsequently polypeptides are identified. Grape tissues, in particular roots, can be very problematic due to their hardness and to the high content of compounds that interfere in classical protein extraction. We have used a phenol-based extraction method in the presence of a protease inhibitor and Polyvinylpolypyrrolidone (PVPP). In this paper we demonstrate that this extraction method gives satisfactory and reproducible protein separation allowing the identification of some proteins by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS).