Fig 1. Comparison of the size distribution of peptides in human cell lines and yeast.

The 627 peptides identified in human cell lines and the 297 peptides identified in yeast were each sorted by rank of the peptide’s molecular mass and plotted. For the human peptidome, the average mass was 1675 Da and the median was 1559 Da. For the yeast peptidome, the average mass was 1640 Da and the median was 1523 Da.