Fig. 4

Changes in protein abundance can be monitored in crude media. A series of measurements with different concentrations of externally-added BSA, were performed in growth media from yeast (a), insect (b), and human (c) cell cultures. The intensity ratio between BSA (dark blue circles) and background reference peaks (labeled with asterisks) was plotted against known BSA concentrations (bottom graphs). A linear trend was found for BSA concentrations of up to 20 µM in yeast and insect cell cultures, and up to 1.4 µM in human growth media. Trend lines and R-squared values are shown. Error bars represent standard deviations of three measurements. The original mean source data is shown in Supplementary Data 2