Early in the 19th century, Swedish chemist Jöns Jacob Berzelius introduced the idea of catalysis — the process by which a chemical substance contributes to a chemical reaction without being changed by it — and suggested that the tissues of all living organisms function through catalytic activity. By the turn of the 20th century, scientists had identified those catalysts as enzymes. Everything we do — motor tasks, decision making, emotional responses — is at its most basic level accomplished by means of enzyme reactions. In the 1940s and ’50s, Stanford Moore and his colleague William H. Stein, two members of The Rockefeller Institute for Medical Research, broke open the field of biochemistry by theorizing how each individual enzyme is programmed to accomplish its own unique catalytic task. They then proved their theories with ribonuclease, an essential regulator of RNA, which translates the genetic information locked in our DNA. For these contributions, Drs. Moore and Stein were awarded the 1972 Nobel Prize in Chemistry.
Proteins, including enzymes, are constructed of amino acids — small compounds of carbon, hydrogen, oxygen and nitrogen. There are 20 different amino acids used by cells in various combinations to create proteins; insulin, for example, is made of 16 amino acids, many of them repeated in a peptide sequence that contains altogether 51 amino acids. This simple mechanism of variation alone explains the ability of an organism to create a myriad of proteins with palpably different structures, like casein, gelatin and silk, and widely varying functions, including hormones, antibodies and enzymes. Drs. Moore and Stein’s main question when they joined Rockefeller concerned how two proteins composed of the same amino acids can have such completely different characteristics and functions. Their hypothesis was that, much like the letters of an alphabet, amino acids have more meaning in their relationships to each other than they do separately, and that the function of a protein is determined by the sequence in which it is arranged.
The first step in determining the sequence of a particular protein was, for Drs. Moore and Stein, to disassemble it. During their first few years at Rockefeller, in the late 1930s, they examined the action of various peptidases and proteinases — naturally occurring enzymes whose function is to break down specific proteins and peptide sequences — to ascertain exactly how they target individual molecules and how they split them apart. They devised numerous methods for artificial catabolism, some of which are still in use today.
Their next step was to identify the now separated components in the “enzyme soup” they had effectively created. They utilized a method known as partition chromatography, whereby they passed their indistinguishable mixture through a porous material — in this case, a glass tube filled with potato starch — which causes the constituent elements to separate from each other and form distinct groups. They then employed a reagent in order to measure the number of amino acids in each group. Over the next several years, Drs. Moore and Stein greatly improved upon this method, and eventually used it to analyze the amino acid content of many biologically significant proteins.
Through continuing experiments, Drs. Moore and Stein discovered several crucial facts about the alphabet of amino acids and the patterns into which they are folded. The structure of an enzyme, they found, is of little importance in determining its specific catalytic activity if the active site of the peptide sequence has not been located. They then devised a way to locate the active site of an enzyme without solving its structure and discovered that the amino acids of the active site are more reactive than the same amino acids in free form. In addition to the research implications of these discoveries, Drs. Moore and Stein contributed to medical science: Their experimental methods offered physicians a way to determine the amino acid constitution of blood serum and of human urine, a now common diagnostic technique for many diseases. Drs. Moore and Stein shared the 1972 Nobel Prize with Christian B. Anfinsen of the National Institutes of Health.
Born in Chicago in 1913, Dr. Moore grew up in Nashville and received his Ph.D. in organic chemistry from the University of Wisconsin in 1938. The following year, he joined the laboratory of Max Bergmann at The Rockefeller Institute, at the time renowned for its innovative research on the chemistry of proteins and enzymes and the place where Drs. Moore and Stein met and began their collaboration together. Following World War II, when Dr. Moore worked for the federal Office of Scientific Research Development in the war effort, he returned to Rockefeller and, under the leadership of institute director Herbert Gasser, continued his research with Dr. Stein. Dr. Moore was a member of the National Academy of Sciences and the American Chemical Society, from which he received the Award in Chromatography and Electrophoresis and the Richards Medal. He died in 1982.