VARIABILITY OF HEALTHY HUMAN PROTEOME
The purpose of this review is to analyze investigations devoted to characteristic of protein variability and diversity of their posttranslational modifications in healthy humans. The numerous researches have demonstrated that proteomic profile has a considerable both intra- and inter-individual variability, and quite often normal variability of some proteins can be comparable to changes observed in pathological processes. Results obtained by our research group have confirmed high intra-individual variability of serum low-molecular subproteome of healthy volunteers, certified by a special medial committee. Proteins characterized by high variability in normal conditions (e.g. haptoglobin - 0-40 mg/ml; lysozyme - 0,01-0,1 mg/ml; C-reactive protein - 0,01-0,3 mg/ml) should be excluded from the list of potential biomarkers. On the contrary, proteins and peptides characterized by insignificant dispersion in healthy population (such as albumin - coefficient of variation (CV) 9%; transferrin- CV 14%; С3с complement - CV 17%, α-1 acid glycoprotein - CV 21%, α2-macroglobulin - CV 20%; transthyretin fragment - CV 28,3% and β-chain α2-HS-glycoprotein - CV 29,7%) can provide us with important information about state of health. Thus investigations of plasticity in proteomic profiles of healthy humans will help to correct reference intervals used in clinical proteomics.