Smith, Hamilton Othanel (1931-…), an American microbiologist, won the 1978 Nobel Prize for physiology or medicine. He shared the prize with Werner Arber of Switzerland and Daniel Nathans of the United States, for their discoveries in molecular genetics.
Genes are made of deoxyribonucleic acid (DNA), and most genes carry coded chemical instructions for the production of proteins. Proteins are essential for the repair and replacement of body tissues. Some proteins, called enzymes, control the chemical reactions that occur within all living things. The structure of a gene–that is, the instructions that are contained in its DNA–determines which protein it makes and when it makes it. Smith discovered a group of restriction enzymes, which break off a molecule of DNA at a specific point so that gene-sized fragments can be produced. This makes it possible for scientists to study the structure of the DNA.
Hamilton Othanel Smith was born in New York City. In 1952, he graduated from the University of California at Berkeley. In 1956, he received his M.D. degree from the Johns Hopkins University School of Medicine in Baltimore, Maryland. He joined the faculty of the University of Michigan in 1962. In 1967, he returned to Johns Hopkins University and, in 1973, he was appointed professor of microbiology there.