suggesting that in all cases the entire complexes were present in the sample and were ‘fished out’ by the affinity ligand. Such is the case of ITI complex proteins ITI-HC1, ITI-HC2, ITI-HC3 and ITI-L, enriched 4.1-, 4.9-, 4.2- and 3.1-fold respectively in the in-matrix digestion sample; apolipoprotein D (APOD) and apolipoprotein A-II (APOA2), which circulate as a disulfide-linked heterodimer