Electrochemical Study of Insulin at the Polarized Liquid-Liquid Interface

Abstract

Insulin is a small protein (RMM ~5700) composed of two polypeptide chains A and B and containing three disulphide bonds, two of which are interchain between A and B, while the third is an intrachain bond within chain A.1,2 Insulin regulates blood glucose by signaling when high levels of blood glucoseare present in the body.3 It stimulates the uptake of glucose by muscle tissue and works together with another hormone, glucagon, to maintain a controlled level of blood glucose. Diabetes mellitus is caused by a deficiency in the secretion (type 1 diabetes) or action (type 2 diabetes) of insulin. According to one study, the prevalence of diabetes for all age groups worldwide is estimated at 2.8% for 2000 rising to 4.4% in 2030.4 The total number of people with diabetes is projected to rise from 171 million in 2000 to 366 million in 2030. Furthermore, the American Diabetes Association (ADA) estimated the national cost of diabetes in the U.S. for 2002 to be $132 billion, increasing to $192 billion in 2020,5 so clearly insulin monitoring is an important subject for medical and physiological studies of this disease.