Miniaturized Mass-Spectrometry-Based Analysis System for Fully Automated Examination of Conditioned Cell Culture Media

Figure 7

MS spectra at 2 hours intervals during standard yeast growth (for figure clarity, every 2nd spectrum is omitted resulting in a 4 hours interval). Marked peaks (legend insert) indicate peptide ions of interest (alpha-N, 882.45 Da: [M + H]⁺ of aminoterminal mating factor hexapeptide; alpha-trunc, 1536.75 Da: carboxy terminally truncated oxidized mating factor (oxidized alpha factor minus C-terminal tyrosine residue); EXG1, 1628.74 Da: fragment of EXG1 membrane protein; alpha, 1683.85 Da and alpha-ox, 1699.83 Da: alpha-mating factor and its oxidized version). Mating-factor-related peptides do not appear at early time points, whereas they become the most abundant ion peaks at later growth stages, which fits with physiological data. Inserts (top left; bottom right) show magnifications of a spectrum with annotated peaks of interest and their isotopes.