Frederick Sanger.

Frederick Sanger was born in Rendcombe, Gloucestershire, England, on August 13, 1918. The son of a physician, he spent his early education at Bryanston School. Sanger attended Cambridge University for his entire university education, earning first a bachelor of arts degree in 1939 and then a doctorate in 1943 through St. John's College at Cambridge. He continued his biochemistry research at Cambridge as a research fellow until 1951, at which time he joined the staff of the Medical Research Council. During the 1940's and 1950's, much chemical research focused on the hereditary molecule deoxyribonucleic acid (DNA) and proteins, the products of DNA. Sanger's primary research interest at this time was in determining the exact amino acid sequence of a protein. In the early 1940's, he experienced a significant breakthrough toward that end. In 1945, he devised a method to use the chemical 2,4-dinitrofluorobenzene, later known as Sanger's reagent, to label one end of the protein chain. Sanger could then use acid to break up the protein into smaller fragments. Other scientists had designed a method to separate the individual amino acids from a mixture called paper chromatography. Sanger planned to break down the sequence of amino acids partially; attach his reagent to one end, break these labeled fragments down to individual amino acids, and separate them using paper chromatography. In this way; he could identify which amino acid was labeled. By painstakingly repeating this procedure many times, he could generate overlapping fragments of the protein and then, as if working a jigsaw puzzle, deduce the order of the amino acids. The protein hormone insulin had been isolated some twenty-five years earlier and was known to consist of two connected chains of fifty amino acids. Sanger chose this protein, which he obtained from the pancreatic tissue of cattle, for his sequence experiment. INSET: Frederick Sanger.