The aim of this study was to optimize a proper method to extract intracellular and extracellular protein from Saccharomyces cerevisiae to construct the proteomic maps. Methods of protein extraction and cultivation condition were optimized. The cells were cultured in YNB medium for 20 h and cells were separated by centrifugation. The extracellular proteins in supernatants were obtained through ultra filtration-freeze drying. Cell pellets were resuspended in SDS lysis buffer. The cell suspension were boiled for 5 min, after solubilized by sonication and stored until use. The intra- or extracellular protein from S. cerevisiae were separated by 2-DE and stained with silver nitrate. The separated protein spots in gels were analyzed by PDQuest. The results showed that over 200 spots of extracellular proteins and about 500 spots of intracellular proteins had been separated by 2-DE.
