Insulin in a polypeptide composed of 51 amino acids divided into two chains (A and B) linked by disulfide bonds. Both chains are organized as alpha helix.|Insulin is produced by the beta cells of the pancreatic islets in form of a precursor (prepro-insulin) and is modified to obtain the pro-insulin (peptide signal elimination) and finally insulin (peptide C elimination).|The main function of the insulin is the regulation of the glucose concentration in the organism. The dysregulation of the production of insulin induced many disorders including diabetes.