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

beta-2-Microglobulin (beta(2)M) is a major protein component found in the amyloid deposits of dialysis-related amyloidosis (DRA) patients. E vidence has been shown that the advanced glycosylated end-products (AG Es) of beta(2)M present in sera were related to DRA, We demonstrated t hat matrix-assisted laser desorption/ionization mass spectrometry (MAL DI-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, Th e high-mass end of beta(2)M-AGE distribution was found to extend to th e 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 det ermine whether beta(2)M-AGEs can be detected by MALDI-MS, In an attemp t to investigate the possibility of quantification with MALDI, human s era samples with different concentrations of beta(2)M-AGE were examine d, We were able to correlate the concentration of beta(2)M-AGE with th e number of detected AGE products, pointing to the feasibility of MALD I as a quantitative tool.