Protein extraction from cowpea tissues for 2-D gel electrophoresis and MS analysis

A method of extraction of proteins from cowpea for two-dimensional electrophoresis is presented. This method avoids loss of protein in the course of sample preparation and results in a fraction that yields reproducible 2-DE protein patterns. The efficiency of this method was demonstrated by comparison of the patterns of protein deposition in developing and mature cowpea seeds. It is also demonstrated that without further processing of the gel piece the proteins present in the spots can be directly digested with trypsin and the peptides subjected to mass spectrometry analysis for identification.