DETECTION AND QUANTITATION OF BETA-2-MICROGLOBULIN GLYCOSYLATED END PRODUCTS IN HUMAN SERUM BY MATRIX-ASSISTED LASER DESORPTION/IONIZATION MASS SPECTROMETRY

摘要

beta-2-Microglobulin (beta(2)M) is a major protein component found in the amyloid deposits of dialysis-related amyloidosis (DRA) patients. Evidence has been shown that the advanced glycosylated end-products (AGEs) of beta(2)M present in sera were related to DRA, We demonstrated that matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a useful tool to investigate the nature of glycosylation of beta(2)M and detection of beta(2)M or beta(2)M-AGEs in human serum, The high-mass end of beta(2)M-AGE distribution was found to extend to the neighborhood of 12 868 Da, corresponding to condensations with seven glucose molecules. We also have shown that both beta(2)M and beta(2)M-AGEs can be detected at low picomole levels directly in bovine serum. Based on these findings, the sera of DRA patients were studied to determine whether beta(2)M-AGEs can be detected by MALDI-MS, In an attempt to investigate the possibility of quantification with MALDI, human sera samples with different concentrations of beta(2)M-AGE were examined, We were able to correlate the concentration of beta(2)M-AGE with the number of detected AGE products, pointing to the feasibility of MALDI as a quantitative tool.