Protein production rate fold change distributions and comparison of medians. The main plot shows distributions of R fold change for four sets of protein pairs, as used previously. For each pair, the R ratio was calculated with the larger value always in the numerator; dashed lines mark median point estimators. Panel A: 95% CIs for distribution medians; n – sample size. Panel B: 95% CIs for differences in medians, with the compared medians indicated by arrows. As both control sets are equivalent, the difference in their medians was calculated twice (random PPIs median minus shuffled PPIs median, and conversely). For a typical co-complex PPI the protein production rate of one protein is 1.77–1.85 times higher than for its partner, while for random protein pairs this ratio is higher by at least 1.59 and equals about 3.40–4.00.