A new effective method for the evaluation of glycated intact plasma proteins in diabetic subjects

Summary The molecular weights of plasma proteins from healthy subjects and from patients with well-or badly-controlled diabetes mellitus have been determined by use of a matrix-assisted laser desorption ionization method, representing a highly accurate technique for the determination of the molecular weight of large biomolecules. Using this approach, different molecular weights of human serum albumin have been found for healthy (66,572–66,694 dalton) and diabetic (66,785–68,959 dalton) subjects. Such differences can be rationalized as being due to the different number of glucose molecules condensed on the protein and/or their further oxidation products; in the case of our diabetic patients this number is in the range of 1.4–14.8. The data show the high validity and specificity of the technique, which allows us to evaluate, without any protein degradation procedure, the number of glucose molecules condensed on a specific protein and ascertain the relationship of this number to the physiopathogenetic conditions of the subjects studied.Abbreviations AGE Advanced glycation end products - FFI 2-(2 furoyl)-4-(5)-(2 furanyl)-1H imidazole - MALDI matrix-assisted laser desorption/ionization - BSA bovine serum albumin - HSA human serum albumin - HbA_1c glycated haemoglobin - Da dalton - NIDDM non-insulin-dependent diabetes mellitus - keV kiloelectron volts - UV ultraviolet