Matrix-assisted laser desorption/ionization mass spectrometric studies on protein glycation. 2. The reaction of ribonuclease with hexoses

The products arising from the reactions of ribonuclease with glucose or fructose have been studied by means of matrix‐assisted laser desorption/ionization mass spectrometry. The reactions have been carried out at physiological pH, with two different sugar concentrations and different incubation times. A maximum increase in molecular weight, corresponding to 485 Da, was found in the case of ribonuclease incubated with 0.25 M fructose for 6 days. Furthermore clear differences have been found in the reactivity of glucose and fructose; in particular, while glucose reacts faster than fructose in the early stage of the glycation, the rearrangements of the Amadori adducts are favoured using fructose as reagent sugar.