Investigation On Electrochemical Properties Of Insulin And The Interaction With Uric Acid

Insulin is a peptide hormones secreted byβcells of pancreatic. Primary structure of insulin contains two peptide chains, which connected with the two disulfide bonds with cystine. And in one chain of insulin, one disulfide bond connected by cysteine across five peptide bonds. The redox reaction of disulfide bond in organisms lead to the biochemical reactions, and related to many important biological functions. Insulin resistance as the main cause of type II diabetes, one of the main reason is that the redox reaction of disulfide causes disulfide bond breaking, which makes the change of insulin structure, and this might induce insulin resistance. The biological effects of insulin are involved in redox reaction, but the study reported rarely about the redox properties of insulin so far, and few reports on the characteristics of molecules and insulin metabolism molecular mechanism of interaction. In this paper, the electrochemical properties of insulin have been investigated and discussed the disulfide bond redox reaction mechanism of insulin through electrochemistry, spectroscopy, and mass spectrometry. Also readox interaction between insulin and uric acid has been investigated in order to get insight into the relationship between diabetes and uric acid in the body.Chapter 1 Perspective of Oxidative Stress and DiabetesIncreasing evidences in both experimental and clinical studies suggest that oxidative stress play a major role in the pathogenesis of both types of diabetes. Free radicals are formed disproportionately in diabetes by glucose oxidation, nonenzymatic glycation of proteins. Abnormally high levels of free radicals can lead to damage of cellular organelles and enzymes, increased lipid peroxidation, and development of insulin resistance. These consequence of oxidative stress can promote the development of complications of diabites mellitus. In this paper, recent progress on the relationship between diabetes and oxidative stress and antioxidative treatment of diabetes have been briefly reviewed.Chapter 2 Investigation on the Electrochemical Properties of InsulinThe electrochemical properties of insulin was investigated through cyclic voltammetry, which used glassy carbon electrode, platinum electrode, and gold electrode as working electrode. The strong coordination of tyrosine residues with Zn2+, which was used as a probe, through the electrochemisity and spectroscopy determined the electrical activity of insulin was the disulfide bond which was across the five peptide bonds instead of tyrosine residues. And proposed the electrode reaction mechanism of the disulfide bonds. At the same time, based on the investigation of the reaction between H2O2 and insulin, it provides a relationship between the oxidative stress and insulin resistance.Chapter 3 Investigation on the Reaction of Insulin with Reduction BiomoleculesHigh blood uric acid in the body usually accompanied by insulin resistance in type II diabetes. This maybe due to the biochemical interaction between uric acid and insulin, which lead the insulin losing its function. In this study, the mixture of insulin and uric acid was determinated by cyclic voltammetry, UV-Vis spectrophotometry and mass spectrometry, and proposed the reaction mechanism. This has provided a direct basis between diabetes and some metabolite which contains the ability of redox. In this paper, also has discussed the reaction of insulin with some reduction molecules, like Ascorbic acid, Glutathione, which are similar as uric acid.