Hamilton O. Smith
The Nobel Prize in Physiology or Medicine 1978
Born: 23 August 1931, New York, NY, USA
Affiliation at the time of the award: Johns Hopkins University School of Medicine, Baltimore, MD, USA
Prize motivation: “for the discovery of restriction enzymes and their application to problems of molecular genetics”
Prize share: 1/3
An organism's genome is stored in the form of long rows of building blocks, known as nucleotides, which form DNA molecules. Werner Arber discovered restriction enzymes, which cut DNA molecules at sites where a certain sequence of nucleotides occurs. Hamilton Smith verified this discovery. Using a purified restriction enzyme taken from a bacterium, in 1970, Smith was able to show that the restriction enzyme cleaves the DNA molecule in the middle of a symmetrical sequence of nucleotides.