Reliability of Protein Abundance and Synthesis Measurements in Human Skeletal Muscle.

The repeatability of dynamic proteome profiling (DPP), which is a novel technique for measuring the relative abundance (ABD) and fractional synthesis rate (FSR) of proteins in humans, is investigated. LC-MS analysis is performed on muscle samples taken from male participants (n = 4) that consumed 4 x 50 mL doses of deuterium oxide ((H2O)-H-2) per day for 14 days. ABD is measured by label-free quantitation and FSR is calculated from time-dependent changes in peptide mass isotopomer abundances. One-hundred one proteins have at least one unique peptide and are used in the assessment of protein ABD. Fifty-four of these proteins meet more stringent criteria and are used in the assessment of FSR data. The median (M), lower-, (Q(1)) and upper-quartile (Q(3)) values for protein FSR (%/d) are M = 1.63, Q(1) = 1.07, and Q(3) = 3.24, respectively. The technical CV of ABD data has a median value of 3.6% (Q(1) 1.7% to Q(3) 6.7%), whereas the median CV of FSR data is 10.1% (Q(1) 3.5% to Q(3) 16.5%). These values compare favorably against other assessments of technical repeatability of proteomics data, which often set a CV of 20% as the upper bound of acceptability.