Reactivity of rare sugar D-allose during glycation of human serum albumin

Summary A rare sugar, D-allose (All), exhibits antioxidant activity, and its application in the fields of medicine and food chemistry can be expected. Glycation of proteins has been thought to evoke an oxidative stress state in vivo, but the detailed process involved is unclear. We estimated the reactivity of All during the glycation of human serum albumin (HSA), which was carried out in the presence of All, D-glucose (Glc), D-fructose (Frc) and D-psicose (Psi). The glycation conditions were at pH 7.4 and pH 9.0, 37℃ for 7 days and 50℃ for 48 hours, respectively. The amount of glycation was measured using a glycated albumin kit (Lucica GA-L), fructosamine assay, MALDI-TOF MS, etc,. All reactivities were 1.93-2.38-fold, 1.83-2.40-fold, and 1.63-2.78-fold higher than Glc in glycated albumin, fructosamine, and molecular mass, respectively. Molecular mass increases were larger at pH 9.0 than at pH 7.4. Our results also revealed that alkaline conditions promoted glycation.