Christian B. Anfinsen

Christian B. Anfinsen (1916-1995), American biochemist and Nobel Prize winner. His research focused on understanding the relationship between a protein's three-dimensional structure and its ability to function in a living cell. For this work, he was awarded a share of the 1972 Nobel Prize in chemistry, along with American scientists Stanford Moore and William H. Stein.

Born in Monessen, Pennsylvania, Anfinsen studied at Swarthmore College and the University of Pennsylvania and received his Ph.D. degree in biochemistry from Harvard Medical School in 1943. He joined the National Institutes of Health (NIH) in 1950, where he first began studying the structure and function of the protein ribonuclease. Like many proteins, ribonuclease functions as an enzyme (a chemical substance that speeds up chemical reactions without being consumed in the process).

A protein molecule is made up of amino acid units bound together to form a long chain. There are only about 20 common amino acids, but more than a hundred amino acid units may be needed to form a single protein molecule. Each type of protein has its own unique sequence of amino acids, which twists and folds in its own distinctively characteristic way. The folding pattern can be as important as the amino acid units themselves, for without the necessary folding, the protein cannot react with other substances. In his studies of the enzyme ribonuclease, Anfinsen found that when he disrupted the linkages that hold in place the molecule's three-dimensional structure, the enzyme became biologically inactive. This holds true even when the chain of amino acids remains intact. Anfinsen also tried to determine what a particular protein's three-dimensional structure would be—out of more than a million possible arrangements. He demonstrated that proteins orient themselves into the most energetically stable formations. This brings certain amino acids close enough together to form the linkages that allow folding to take place. Anfinsen concluded that a specific and unique sequence of events must occur to produce proper folding in the protein. This important discovery allowed other scientists to successfully link up amino acids to form synthetic enzymes that are biologically active.