Cornforth (Cornforth), John W.( Australian organic chemist Nobel Prize in Chemistry, 1975)
Comments for Cornforth (Cornforth), John W.
Biography Cornforth (Cornforth), John W.
genus. September 7, 1917
Australian organic chemist Uorkap John Cornforth was born in Sydney, the son of an Englishman Dzh.U. Cornforth and a native of Australia, Hilda (Eypper) Cornforth, whose parents were German-born. As a child, to. lived in Sydney and rural New South Wales. At the age of 10 he had the first signs of hearing loss from otosclerosis - diseases associated with the growth of bone tissue in the middle and inner ear, and after 10 years to. completely deaf. Serious interest in chemistry came from the future back in scientist years of study at Sydney High School for Boys. And the 'guilty' in that it was a school teacher.
In 1933. K. enrolled in the University of Sydney, and 4 years later he graduated with honors, receiving the university medal. After a one-year diploma in chemistry, he and Rita X. Harradens, student of Organic Chemistry, University of Sydney, won a scholarship to have an education at Oxford University. In 1939, when young people went to study in England, the Second World War. In London, in the laboratory of Robert Robinson, they studied the synthesis of steroids, organic molecules contain a flat four-membered cyclic structure with different side chains. Among the naturally occurring steroid mammals include: cholesterol, male and female sex hormones (androgens and estrogens), adrenokortikosteroidy (such as cortisone), and bile acids. In 1941, Mr.. K. Harradens and Rita were married, and in the same year, each of them the University of Oxford was awarded a doctoral degree in chemistry.
During the war years to. continued study of steroid synthesis and chemical structure of penicillin, Alexander Fleming Open. Penicillin was extremely effective in treating wound infections and pneumonia. Results of studies to. in this direction were reflected in the published in 1949. report on the work of scientists around the world to synthesize the antibiotic, called 'Chemistry of Penicillin'. Spouses Cornforth worked in the laboratory of the Medical Research Council from 1946 to 1962
Cholesterol, naturally occurring steroid, is a component of biological membranes and is the basis of steroid hormones and bile acids. Cholesterol molecule containing 27 carbon atoms, 19 of which are tetracyclic ring system, and 8 - the lateral carbon chain. In 40-ies. Konrad Bloch proved, . that the synthesis of cholesterol in biological systems begins with the molecule apetilkofermenta A (biologically activated form of acetic acid), . from which the origin of all carbon atoms of cholesterol (in the synthesis of cholesterol involves only 2 atoms atsetilkofermenta A),
. Three molecules atsetilkofermenta A connected with the formation of molecule 3-hydroxy-3-methylglutaryl-coenzyme A, which was based on a fragment of 6 carbon atoms, which is reduced to mevalonic acid, which has shestiuglerodnuyu molecule. Mevalonic acid is then converted into pyatiuglerodny isopentyl enilpirofosfat that passed through a series of stages of condensation, forms squalene. This tridtsatichlenny hydrocarbon tsikliziruetsya to lanosterol and ultimately the loss of three carbon groups formed cholesterol. Applying the method of introducing the tracer, K. and his colleague George Popzhak showed structural position of each molecule of acetic acid in cholesterol and, moreover, identified 24 intermediate stage between mevalonic acid and squalene. Rita Cornforth synthesized labeled precursor mevalonic acid.
In 1962. K. and Popzhak were appointed co-director of the laboratory enologist company 'Shell Research Limited,' in Sittingbourne (Kent), near London. From 1965 to 1971. K. simultaneously worked an associate professor in the School of Molecular Sciences University of Warwick.
To. Popzhak and focused on the stereochemistry (three-dimensional geometry of the atoms) molecular interactions between enzymes and their substrates in the synthesis of squalene from mevalonic acid. They systematically labeled with each of the 6 methylene hydrogens in the mevalonic acid, deuterium or tritium (isotopes of hydrogen). Combining the introduction of radioisotopes, enologist, synthesis methods, the method of chemical degradation and sensitive measurements of physical parameters, K. and Popzhak finally proved that all interactions of the enzyme - substrate between mevalonic acid and squalene are stereospecific, ie. as a result of their interactions formed certain stereoisomer. In addition, they found that the interaction of the enzyme - substrate (intermediate in the biosynthesis of terpenoid compounds) are also stereospecific. Terpenoids are derivatives of terpenes - substances that form the basis of natural resins and oils. Terpenoids, like squalene, are formed from mevalonic acid.
To. and Popzhak identified as a hydrogen atom of coenzyme NADN (reduced nicotinamide-adenine-dinucleotide), which is transferred by molecular oxygen in biological redox reactions. Twenty-year collaboration to. with Popzhakom ended in 1968, when Popzhak accepted the appointment to the University of California at Los Angeles.
Stereochemical phenomenon of molecular symmetry and asymmetry can be illustrated by the following examples. Valency (the ability to chemically bound) carbon atom is 4 (he can communicate with 4 other atoms or molecules). If the carbon atom is connected with 4 normal hydrogen atoms (H), . then formed as a result of the molecule of methane (CH4 or SNNNN) has the geometrical structure of a symmetric tetrahedron, . in which the central carbon atom surrounded by 4 atoms of hydrogen, . each of the past located in the corner of the tetrahedron,
. If deuterium, or heavy hydrogen (D), replaces one of the hydrogen positions of methane, it becomes SNNNN CDNNN. It is believed that methane deytirovanny artificially asymmetric around the carbon atom. Hydrogen positions of methane can be replaced by larger molecular groups. Rule of symmetry and asymmetry remains in force for the larger organic molecules.
. According to K., the purpose of its work was to 'reveal hidden asymmetry, chirality, stereospecificity in life processes through the study of asymmetry, which is available for study'
. Chirality - a stereochemical property, indicating the incompatibility of the object with its mirror image. Since 1967. K. in collaboration with the German chemist Hermann Eggererom worked on the problem of chiral methyl group - methyl group with normal, deytirovannymi and treated with hydrogen atoms. They carried out technically complex synthesis and enzymatic analysis of compounds containing the chiral methyl group. Then K. and his colleagues used a chiral methyl-labeled acetic acid for further study of the stereochemistry of reactions of the enzyme - substrate. They found not only what kind of a hydrogen atom is transferred during the condensation of molecules izopentenil-pyrophosphate (an intermediate stage in the biosynthesis of cholesterol), but the origin of all 50 hydrogen atoms in squalene. Besides, . scientists proved, . that stereospecificity is crucial for enzyme activity, . that it can be hidden or implicit, and detected only by stereochemical analysis and, . Finally, . that the stereospecificity of the reactions of the enzyme - substrate does not depend on the structural relationship of the substrate with the product.,
. In 1975
. K. was awarded the Nobel Prize in Chemistry 'for the study of the stereochemistry of reactions of enzymatic catalysis'. The scientist was awarded it jointly with Vladimir Prelog. At a ceremony to. gave the following description of the figurative process of scientific inquiry: 'In a world where so easy to ignore, deny, distort and suppress the truth, the scientist often finds that he shouldered a very heavy burden. Truth for him - a rare visitor. She, like a sudden glittering beam of light illuminates, snatching out of the darkness a new order and beauty. Much more frequently, it resembles uncharted reef, which heats the ship in darkness. Therefore worthy of respect for someone who is ready to accept such a search of the truth ... and facilitate the wearing of scientists, sharing it with them '.
After retiring in 1975. retired from the Laboratory of Chemical enologist, K. was appointed professor, University of Sussex. This post is a scientist held for seven years. Cornforth The couple worked together for many years in the chemical laboratory. Now they live in Saxony-Downs (county of East Sussex). They have a son and two daughters. K. likes to relax by playing tennis and chess, working in the garden.
To. has been awarded many prizes. Among them: Corday-Morgan Medal (1953) and Flintoff Medal (1966) British Society of Chemistry, . Medal 'Ciba' British Biochemical Society (1966), . Davy Medal (1968), . Royal Medal (1976) and Copley Medal (1982) Royal Society of London,
. He was awarded honorary degrees from Oxford University, the University of Dublin, Liverpool, Warwick, Aberdeen and Sydney.