Protein extracts of Saccharomyces cerevisiae CEN.PK113-7D cultivated in chemostats under different conditions. Representative samples containing aliquots of all conditions were spiked with UPS2 standard (Sigma) to estimate absolute values in fmol. The conditions for Saccharomyces cerevisiae CEN.PK113-7D are: T2- Standard condition : 30°C, pH 5.5 T3- High temperature: 36°C, pH 5.5 T4- Low pH: 30°C, pH 3.5 T5- Osmotic stress : 30°C, pH 5.5, 1M KCl T6- Anaerobic condition Furthermore, representative samples pooling aliquots of each condition are indicated as "bulk" samples. These samples were spiked with UPS proteins. A validation step was carried out by spiking 4 external proteins at known concentrations within the yeast and UPS proteins mixture