To assay different concentrations of arginine and glycine as two osmolytes on human islet amyloid polypeptide conformation under experimental setting

Abstract

Aggregation of amylin peptide that cosecretes with insulin has an important role in the pathogenesis of type 2 diabetes. Hence, inhibition of the formation of beta-amyloid fibrils would be an ideal goal for management of diabetes. Here, we investigated the inhibitory effect of glycine and arginine on the amylin aggregation in experimental conditions. Using fluorescence spectrographic analysis with thioflavin T and visualization of amyloid fibers by atomic force microscopy, different concentrations of arginine and glycine were evaluated on amylin conformation under nearphysiological circumstances. The results obtained from the in vitro study showed that 240 h incubation by shaker incubator at 37 degrees C, arginine with concentration of 50, 100 and 150 mu mol/L inhibited fibril formation significantly (P <0.001). However, at 10 mu mol/L, it had insignificant effect on human isle amyloid peptide conformation. The obtained data also demonstrated that glycine with concentrations of 50, 100 and 150 mu mol/L had inhibitory effects on formation of beta-amyloid sheet significantly (P <0.001). It may be concluded that isle amyloid toxicity to beta-cells may be reduced by the two amino acids so that these compounds are suggested for development of new therapeutics for diabetes.