A MALDI-TOF mass spectrum of a known ratio of 1∶1∶1∶1 peptides consisting of 300 nM Ang-(2–10), Ang-(1–9), SIS-Ang-(2–10) and SIS-Ang-(1–9).

<p>The spectrum has been fit using GMM and the figure shows how each estimated peptides contributes to the whole spectrum. Since all peptides are estimated simultaneously, each peptide is presented here separately to illustrate the individual contribution of each peptide to the spectrum as a whole. (A) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0111016#pone-0111016-g003" target="_blank">Figure 3a</a> shows the entire estimation as a whole, preformed as a single fit to a single cluster of four overlapping peptides. The data is shown in black with the estimated peaks superimposed in red. (B) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0111016#pone-0111016-g003" target="_blank">Figure 3b</a> shows the estimated contribution of Ang-(2–10) to the spectra superimposed in blue. (C) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0111016#pone-0111016-g003" target="_blank">Figure 3c</a> shows the estimated contribution of Ang-(1–9) to the spectra superimposed in green. (D) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0111016#pone-0111016-g003" target="_blank">Figure 3d</a> shows the estimated contribution of SIS-Ang-(2–10) to the spectra superimposed in dark yellow. (E) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0111016#pone-0111016-g003" target="_blank">Figure 3e</a> shows the estimated contribution of SIS-Ang-(1–9) to the spectra superimposed in dark purple.