Quantitative determination of the series of blood serum markers without its preliminary fractionation using the special features of tripsine interaction with alpha-2-macroglobulin using MALDI-MS

Concentration of alpha-2-macroglobulin (α2-MG) in serum may vary considerably in a number of diseases, and thus quantification of this protein is used in diagnostics. Routine immunological or enzymatic methods for determination of α2-MG concentration in serum are rather complicated. The methods require specific antibodies or the measurements of specific substrates hydrolysis rates. These tests do not distinguish the α2-MG free form from its bound form. We propose a new mass-spectrometric approach to identify and quantify some blood serum biomarkers. The method is based on structural-functional characteristic properties of α2-MG interaction with trypsin, characterized by the cleavage of VGFYESDVMGR peptide. Technique of isotope exchange (18O) was developed for the preparation of internal standard, including direct isotope exchange in blood serum. The quantitative potential of the proposed technique turns mass-spectrometry (MALDI) into a suitable and efficient tool for diagnostics of inflammatory processes...