Mitochondrial metabolomics in Saccharomyces cerevisiae

Mitochondria play a key role in the energy metabolism and redox control of the cell. They also have important functions in apoptosis and the metabolism of amino acids, lipids and iron. Recently, the knowledge about mitochondria have been widened by proteomic and transcriptional studies, but a lot still remains unknown. We are therefore aiming to study the mitochondrial metabolism of Saccharomyces cerevisiae as a whole and compare it to overall cellular metabolism. We are going to do metabolic profiling of isolated mitochondria by using LC/MS, GC/MS and NMR methods. New computational and statistical methods are developed and applied to tract subtle changes in spectral data, which leads to identification of compounds most descriptive of various physiological responses. We have already made preliminary studies on glucose grown yeast cells and have been able to show differences between the mitochondrial and whole cell metabolites. Based on 2627 peaks detected using LC/MS we could separate the metabolites with principle component analysis; with 140 peaks we could differentiate the compartments with p>0.05. Ultimately, we are aiming to relate these studies to the physiological status of the cell by comparing the data from metabolite level with transcriptional and proteomic data. We believe that this may reveal us a more complete picture of the mitochondria and at the same time the whole metabolism occurring in the yeast cell.