Potassium sorbate as an AGE activator for human serum albumin in the presence and absence of glucose

Abstract

Advanced glycation end products (AGEs) are the predominant intermediates of glycation process, and mediate oxidative stress and complications of diabetes. Potassium sorbate (PS) as a widespread preservative is an oxidative agent and used in different dairy and drug products, which can readily enter biological matrices. Here we studied the PS interference with glycation of human serum albumin (HSA) in the presence of glucose (Glc) using various techniques. These included TNBSA assay, circular dichroism, fluorescence spectroscopy, differential scanning calorimetry (DSC), Th T assay, and atomic force microscopy. Our results indicated that HSA glycation was accelerated in the presence of PS. Furthermore, PS produced AGEs in the absence of glucose. Secondary and tertiary structural changes were also observed in HSA incubated with glucose in the presence or absence of PS through beta-sheet inducing effects. Th T assay demonstrated the role of PS in HSA fibril formation in the presence or absence of glucose. Atomic force microscopy determined different amyloid fibril formation in HSA incubated with PS in the presence or absence of glucose. Together our results indicated that PS has a stimulatory effect on glycation and fibrillation of HSA in the presence or absence of glucose, and could exacerbate complication of diabetes.

Keywords: 2,4,6-trinitrobenzene sulfonic acid; AFM; Advanced glycation end products; BCA; BSA; CD; D; DSC; Glc; Glycation; HSA; Human serum albumin; PS; Potassium sorbate; TNBSA; Th T; atomic force microscopy; bicinchoinic acid; bovine serum albumin; circular dichroism spectroscopy; days; differential scanning calorimetry; fibril formation; glucose; human serum albumin; potassium sorbate; thioflavin T.