Celebiography.net

John Cornforth

Picture of John Cornforth

Date of Birth: 09/07/1917

Age: 96

Place of birth: Sydney

Citizenship: Australia

Background

In 1933 Karl entered the University of Sydney, and 4 years later he graduated with honors, receiving a university medal. After a one-year diploma in chemistry, he and Rita H. Harradens, student of Organic Chemistry of the University of Sydney, won a scholarship to enable an education at Oxford University. In 1939, when young people went to study in England, World War II began. In London, in the laboratory of Robert Robinson, they studied the synthesis of steroids, organic molecules which contain a flat four-term cyclic structure with a variety of side chains. Among the naturally occurring mammalian steroids include: cholesterol, male and female sex hormones (androgens and estrogens), adrenocorticosteroids (such as cortisone) and bile acids. In 1941, K. and Rita Harradens married, and in the same year, each of them Oxford University was awarded a doctoral degree in chemistry.

During the war, Karl continued to study steroid synthesis and chemical structure of penicillin, Alexander Fleming open. Penicillin was extremely effective in the treatment of wound infections and pneumonia. The results of the research in this direction K. were reflected in published in 1949 a report on the work of scientists from different countries of the world on the synthesis of the antibiotic, called "Chemistry of penicillin." Spouses Cornforth worked in the Medical Research Council Laboratory from 1946 to 1962

Cholesterol, a naturally occurring steroid which is the component of biological membranes and forms the basis of steroid hormones and bile acids. Cholesterol molecule contains 27 carbon atoms, 19 of which are tetracyclic ring system, and 8 - the side carbon chain. In 40-ies. Konrad Bloch showed that cholesterol synthesis in biological systems apetilkofermenta molecule begins with A (biologically activated form of acetic acid) which occur in all carbon atoms of cholesterol (in cholesterol synthesis involving only 2 atoms of acetyl coenzyme A). Three molecule acetyl coenzyme A molecules combine to form a 3-hydroxy-3-methylglutaryl-coenzyme A, which is based on a fragment of 6 carbon atoms, which is reduced to mevalonic acid having six-carbon molecule. Mevalonic acid is then transformed into a five-carbon isopentyl enilpirofosfat that, after going through a series of stages of condensation forms squalene. This tridtsatichlenny hydrocarbon cyclized to lanosterol, and the loss of ultimately three carbon groups forms cholesterol. Applying the method of introducing the tracer, and its counterpart K. George Popzhak showed structural position of each molecule of acetic acid in cholesterol and, moreover, the intermediate stage 24 identified between mevalonic acid and squalene. Rita Cornforth synthesized labeled mevalonic acid precursors.

In 1962, K. and Popzhak were appointed co-director enzymology laboratory of the company "Shell RESEARCH Limited" in Sittingbourne (Kent), near London. From 1965 to 1971 K at the same time was an associate professor in the School of Molecular Science of the University of Warwick.

K. Popzhak and focused on the stereochemistry of the (three-dimensional geometry atoms) molecular interactions between enzymes and their substrates in the synthesis of squalene from mevalonic acid. They were labeled systematically every 6 methylene hydrogens of mevalonic acid in deuterium or tritium (hydrogen isotopes). Combining administration of radioisotopes Enzymology, methods of synthesis, chemical degradation method and sensitive measurement of physical parameters, and K. Popzhak finally proved that all the interactions of the enzyme - substrate between mevalonic acid and squalene are stereospecific, ie as a result of their interactions formed a specific stereoisomer. Furthermore, they found that the interaction of the enzyme - substrate (intermediate in the biosynthesis of terpenoid compounds) are also stereospecific. Terpenoids are derivatives of terpenes - the substances that form the basis of natural resins and oils. Terpenoids, like squalene, are derived from mevalonic acid.

And K. Popzhak also identified hydrogen coenzyme NADN (reduced nicotinamide adenine dinucleotide), which carries oxygen in the molecular biological redox reactions. Twenty-year collaboration with K. Popzhakom ended in 1968, when Popzhak accepted an appointment to the University of California, Los Angeles.

Stereochemical phenomenon of molecular symmetry and asymmetry can be illustrated by the following examples. Valence (the ability to chemically bind) carbon atoms is 4 (it can communicate with 4 other atoms or molecules). If the carbon atom bound to 4 normal hydrogen atoms (H), then formed as a result of the methane molecule (CH4 or SNNNN) has a geometrical structure of a symmetrical tetrahedron, in which the central carbon atom is surrounded by 4 hydrogen atoms, wherein each of the latter lies at the corner of the tetrahedron. If deuterium or heavy hydrogen (D), displaces one of the hydrogen positions methane, it becomes SNNNN CDNNN. It is believed that methane deytirovanny artificially asymmetrical around a carbon atom. Hydrogen positions methane may be replaced by larger molecular groups. The rule of symmetry and asymmetry remains valid for the larger organic molecules.

According to K., the purpose of its work was to "reveal the hidden asymmetry, chirality, stereospecificity in life processes by studying the asymmetry, which is available for the study." Chirality - a stereochemical property, meaning incompatibility object with its mirror image. Since 1967 Karl in collaboration with the German chemist Hermann Eggererom worked on the problem of chiral methyl group - a methyl group with normal deytirovannymi slighted and hydrogen atoms. They carried out technically complex enzyme synthesis and analysis of compounds having a chiral methyl group. Then Karl and his colleagues used a chiral methyl-labeled acetic acid to further study the stereochemistry of enzyme reactions - substrate. They found not only tolerated kakoyimenno hydrogen molecules upon condensation isopentenyl pyrophosphate (an intermediate stage in the biosynthesis of cholesterol), and the origin of the 50 hydrogen atoms in squalene. Moreover, scientists have shown that the stereospecificity is critical for enzyme activity, it can be hidden or implicit and detected only by the stereochemical analysis and finally that the stereospecificity of the enzyme reactions - the substrate is not dependent on the structural relationship of the substrate to the product.

In 1975, K. was awarded the Nobel Prize in Chemistry `for the study of the stereochemistry of enzyme-catalyzed reactions. " The scientist was awarded her together with Vladimir Prelog. At the award ceremony, K. gave the following characterization of shaped scientific research process: "In a world where it is so easy to ignore, deny, distort and gloss over the truth, the scientist often finds that he took upon himself a very heavy burden. Truth for him - a rare visitor. It is like suddenly lighteneth beam of light illuminates, snatching new order and beauty from the darkness. Much more frequently, it resembles not marked on the map the reef, which heats the ship in darkness. Therefore, he is worthy of respect, who are ready to take tons Which search term truth ... and ease the burden of scientists, sharing it with them. "

After retiring in 1975, resigned from the laboratory of chemical enzymology, K. was appointed professor at the University of Sussex. This post is a scholar held for seven years. Spouses Cornforth many years worked together in a chemistry lab. Now they live in the Saxon-Down (East Sussex). They have a son and two daughters. Karl likes to relax by playing tennis and chess, working in the garden.

K. was awarded many prizes. Among them: Medal Corday-Morgan (1953) and a medal Flintoff (1966) British Society of Chemistry, the medal "Shiba" British Biochemical Society (1966), Davy Medal (1968), the Royal Medal (1976) and the Copley Medal (1982), London royal society. He was awarded honorary degrees from the University of Oxford, University of Dublin, Liverpool, Warwick, Aberdeen and Sydney.