Insulin

Prior to the twentieth century, diabetes was a fatal disease. Its cause was unknown, and the method of treating it had yet to be discovered. Not until 1921 did the research of Sir Frederick Banting, a Canadian surgeon, and Charles Best, a Canadian physiologist, reveal that insulin is crucial in blood glucose regulation. The two scientists then isolated insulin, an achievement for which they were awarded the Nobel Prize. Their work was built on previous research by Paul Langerhans, a German pathologist who described the irregular, microscopic collections of cells scattered throughout the pancreas. These later were named the islets of Langerhans and were found to be the source of insulin secretion.

In 1952, a British biochemist, Frederick Sanger, analyzed insulin and discovered it was made up of two chains of amino acids. One chain, called the alpha chain, has 21 amino acids and the second chain, the beta chain, has 30 amino acids. The chains run parallel to each other and are connected by disulfide bonds (made up of two sulfur atoms). With the discovery of the chemical structure of insulin, efforts to synthesize it began.