Fig. 1

The distribution of p values (or X_corr values) versus the peptide expected [M + H]⁺ of C4B from the random and independent sampling degraded plasma. The log₁₀ expectation values (p values) from MASCOT, OMSSA, X!TANDEM and (or X_corr values) SEQUEST algorithms are plotted against peptide [M + H]⁺ values. a MASCOT a heuristic probability-based MOWSE score algorithm; b OMSSA a heuristic probability algorithm; c X!TANDEM a goodness of fit algorithm; d SEQUEST a modified Pearson cross correlation algorithm (X_corr). C4B was the most commonly observed protein by many independent peptides in room temperature samples