Diabetes and mass spectrometry

Mass spectrometry (MS) has been successfully employed to investigate nonenz ymatic protein glycation, a process relevant in diabetic disease. The high sensitivity and specificity of this technique allowed the development of me thods that can individuate and evaluate some glycation markers to be validl y employed in monitoring diabetes. More recent mass spectrometric technique s, such as the matrix-assisted laser desorption/ionization (MALDI), are abl e to determine the molecular weight of intact proteins. They were first emp loyed in studying the in vitro reaction between hexoses and different prote ins. Once the validity of the results obtained by this analytical approach was confirmed, a series of investigations on plasma proteins were undertake n in healthy and diabetic subjects. The method led to the evaluation of the number of glucose molecules condensed on the protein being studied, and co nsequently can be validly used for an accurate follow-up of metabolic contr ol in diabetic patients. When applied to studies on haemoglobin glycation, the method showed that both alpha- and beta -globins are glycated to a simi lar extent and that the simply glycated molecules are accompanied by glyco- oxidized species therefore giving information on the oxidative stress exper imented on in the subject. Furthermore, in the case of immunoglobulins, MAL DI/MS was able to determine not only the total glycation level of IgG, but also to establish that the fragment antigen binding (Fab) moiety is the mos t glycated one, thus suggesting that the possible immunological impairment sometimes invoked in diabetes is related to the inhibition of the process o f molecular recognition between antibody and antigen. Copyright (C) 2001 Jo hn Wiley & Sons, Ltd.