The Study On The Function Of Yeast Extracellular Protein

Saccharomyces cerevisiae is not only an important common microorganism in the industrialapplication, but also becomes a very perfect model organism for research in eukaryotic cell inboth Molecular Biology and Metabology. While numerous proteomic analyses have beencarried out on S. cerevisiae, there were few studies done about extracellular protein whichwere reported by recent research that they may play important effects on the growth ofmicroorganism.In this study, we have optimized a proper method to extract intracellular and extracellularprotein from S. cerevisiae FFC2146to construct the proteomic maps. Methods of proteinextraction and cultivation condition were optimized: The cells were cultured in YNB mediumfor20h and cells were separated by centrifugation. The extracellular protein in supernatantwas obtained through ultra filtration-freeze drying. Cell pellets were resuspended in SDS lysisbuffer. The cell suspension were boiled for5min, after solubilized by sonication andthiourea/urea lysis buffer the protein samples were stored until use. The intracellular andextracellular protein from S. cerevisiae were separated by2-DE and stained with silver nitrate.The separated protein spots in gels were analyzed by PDQuest. The results showed that over200spots of extracellular proteins and about500spots of intracellular proteins have beenseparated by2-DE.And then we got rid of the influence factors (nutrition; organic acid; lipid; space;inhibitor and so on) to discuss the effects of extracellular protein of S.cerevisiae FFC2146onthe organic acid accumulation and strain growth of S.cerevisiae FFC2144and S.cerevisiaeFFC2146. The methods of the research: S.cerevisiae FFC2146and S.cerevisiae FFC2144were cultured with or without extracellular protein which was extracted from20hourscultured S.cerevisiae FFC2146and then by the HPLC and2-DE we analysis the changes ofthe curve of yeast population, the organic acid accumulation and the types and quantities ofprotein in the yeast cell. The results indicate that20hours cultured S.cerevisiae FFC2146 extracellular proteins (EP) have potential effects on both population evolution andaccumulation of organic acid by change the quantity and the species of intracellular protein.