Fig. 2.

Performance of a multiplex SRM assay in the verification phase. A, Endogenous peptides and heavy peptide internal standards were multiplexed in a single SRM assay. B, Representative calibration curves used to quantify TGM4 protein in 67 negative biopsy and 152 PCa SP digests distributed between six 96-well plates. Similar curves were obtained for the rest of proteins (supplemental Fig. S8). Light-to-heavy ratios for TGM4 in each sample were plotted against the corresponding calibration curve, to derive TGM4 concentrations. C, Representative SRM transitions for the light endogenous and heavy internal standard peptides for TGM4 protein.