Budding yeast has from the beginning been a major eukaryotic model for the study of metabolic network structure and function. This is attributable to both its genetic and biochemical capacities and its role as a workhorse in food production and biotechnology. New inventions in analytical technologies allow accurate, simultaneous detection and quantification of metabolites, and a series of recent findings have placed the metabolic network at center stage in the physiology of the cell. For example, metabolism might have facilitated the origin of life, and in modern organisms it not only provides nutrients to the cell but also serves as a buffer to changes in the cellular environment, a regulator of cellular processes, and a requirement for cell growth. These findings have triggered a rapid and massive renaissance in this important field. Here, we provide an introduction to analysis of metabolomics in yeast.
METABOLOMICS IN YEASTResearch on metabolism and metabolic enzymes dominated the early days of molecular biology. Interest in the topic decreased with the appearance of polymerase chain reaction (PCR) and molecular genetics during the 1980s and 1990s, although the importance of budding yeast in biotechnology ensured continued progress in the understanding of its physiology. Yeast has been used in winemaking, brewing, and baking since ancient times. The economic importance of fermentation triggered the first attempts to breed and manipulate yeast species and led to the purification, crystallization, and characterization of the first enzymes in the early 20th century (with major contributions from Sumner and Northrop in the United States and Warburg in Germany). Yeast experiments were so important in the development of biochemistry that the word "enzyme" is derived from the Greek word for in leaven (yeast).The full set of metabolic reactions in the cell is referred to as the metabolic network. Although complex, the basic structure of the metabolic network is largely conserved among organisms, indicating that it is of a common evolutionary origin (Jeong et al. 2000;Ravasz et al. 2002). Compared with the large number of chemical reactions and possible mechanisms, metabolism operates with only a subset of the reactions and prefers short paths in its functionality (Noor et al. 2010). Overall, this conservation means that metabolomics is a particularly attractive technique, as in principle any analytical method can be applied to a large variety of different species. However, sample preparation methods are species specific, because composition of the cell membrane, presence of a cell wall, cellular resistance to physical parameters, and relative and absolute metabolite content differ from species to species.