Recovery of the pro-MPO-, MPO-specific and mutual peptide after affinity purification, tryptic digestion and detection by LC-MS/MS.

Plasma was spiked with one μg of total MPO containing either 90% MPO and 10% pro-MPO or vice versa, subjected to affinity purification with MPO-specific antibodies, digested with trypsin and analyzed by SRM-based LC-MS/MS. The area under the curve (AUC) for the pro-MPO-specific peptide, mature MPO-specific peptide and the mutual peptide are shown (see Fig 4). Data are presented as means ± range of two independent experiments.