KORNBERG, ARTHUR

born March 3, 1918, Brooklyn, N.Y., U.S. American biochemist and physician who received (with Severo Ochoa) the 1959 Nobel Prize for Physiology or Medicine for discovering the means by which deoxyribonucleic acid (DNA) molecules are duplicated in the bacterial cell, as well as the means for reconstructing this duplication process in the test tube. At the U.S. National Institutes of Health, Bethesda, Md. (194253), Kornberg directed research on enzymes and intermediary metabolism. He also helped discover the chemical reactions in the cell that result in the construction of flavine adenine dinucleotide (FAD) and diphosphopyridine nucleotide (DPN), coenzymes that are important hydrogen-carrying intermediaries in biological oxidations and reductions. Appointed professor and director of the microbiology department at Washington University, St. Louis, Mo. (195359), he continued to study the way in which living organisms manufacture nucleotides, which consist of a nitrogen-containing organic base linked to a five-carbon sugar ringribose or deoxyriboselinked to a phosphate group. Nucleotides are the building blocks for the giant nucleic acids DNA and RNA (ribonucleic acid, which is essential to the construction of cell proteins according to the specifications dictated by the message contained in DNA). This research led Kornberg directly to the problem of how nucleotides are strung together (polymerized) to form DNA molecules. Adding nucleotides labeled with radioactive isotopes to extracts prepared from cultures of the common intestinal bacterium Escherichia coli, he found (1956) evidence of an enzyme-catalyzed polymerization reaction. He isolated and purified an enzyme (now known as DNA polymerase) thatin combination with certain nucleotide building blockscould produce precise replicas of short DNA molecules (known as primers) in a test tube. Kornberg was professor of biochemistry at Stanford University, Palo Alto, Calif., from 1959. From 1959 to 1969 he was department chairman. His writings include Enzymatic Synthesis of DNA (1961).