Table 1.

Reproducibility analysis

	LMW Peptides Detected in 5 Extractions of 5 Samples
MS Intensity Quartiles	Detected in 1 sample	Detected in 2 sample	Detected in 3 sample	Detected in 4 sample	Detected in all 5 samples
1 (low)	6 ± 3	20 ± 4	45 ± 10	117 ± 12	260 ± 9
2	3 ± 3	5 ± 1	17 ± 4	78 ± 11	346 ± 5
3	2	3 ± 1	10 ± 1	42 ± 5	392 ± 5
4 (high)	1	3 ± 1	5 ± 1	21 ± 2	420 ± 7
Sum of all intensities	12 ± 2	31 ± 8	77 ± 18	258 ± 42	258 ± 42
%Total LMW (total = 1,796)	0.7%	1.7%	4.3%	14.4%	79.0%

Data are means ± SD number of peptides Reproducibility analysis from 5 extracts from the same muscle sample (rat quadriceps) were analyzed 5 times and revealed that low-molecular-weight (LMW) peptides were consistently detected between biological replicates (e.g., overlapping between samples), with greater detection of peptides at higher intensities. Mass spectrometry (MS) intensities were separated into quartiles from 1 (low) to 4 (high).