MITCHELL Peter D.( English biochemist, Nobel Prize in Chemistry, 1978)
Comments for MITCHELL Peter D.
Biography MITCHELL Peter D.
genus. September 29, 1920
English biochemist Peter Dennis Mitchell was born in Mitcheme (Surrey), in the family of an employee Christopher Gibbs Mitchell and Beatrice Dorothy (Teplan) Mitchell. He graduated from King's College in Taunton, where he studied with Teaspoon. Wiseman, a mathematician and musician. However, the entrance examinations to Jesus College, Cambridge M. passed so bad that if it were not for a letter of recommendation Wiseman, would not have been taken there in 1939
Cambridge M. studied chemistry, physiology, biochemistry and mathematics, and in 1943. received a bachelor's degree with honors. In the same year he started preparing a doctoral thesis in biochemistry under the guidance Dzh.F. Danielli, in the laboratory which carried out the research transfer process of biochemical substances through cell membranes, while continuing to study biochemistry. In 1950, Mr.. he was awarded a doctorate for a thesis on the mechanism of action of penicillin - the Open in 1928. Alexander Fleming's antibiotic which affects cell membranes, have been subjected to 'attack' bacteria.
After receiving his doctorate M. was appointed demonstrator Biochemical Department, Cambridge. Here M. investigated the mechanism of oxidative phosphorylation (that is formed by 95 per cent of energy in aerobic organisms) and is very similar to it a mechanism of photosynthetic phosphorylation (in which a large number necessary for its vital power plants get from the sun),
. While these two mechanisms have been among the major unsolved problems of biochemistry.
The question of how organisms generate energy, they convert it and use the motion and biosynthesis, served not only Moscow but also other scientists. By 1955, Mr.. biochemists have recognized the theory of Fritz Lipmann, according to which adenosine triphosphoric acid (ATP) serves as a universal source of energy. Features of metabolic processes, such as respiration, fermentation and photosynthesis, are impossible without ATP, tk. namely, it supports a variety of energetic processes through its energy-rich phosphoryl bonds. Thus, clearly visible in the main outlines of bioenergy (the science of the transfer of energy by living organisms), could only work out the details at the molecular level.
. This problem, . however, . was extremely difficult, . because the enzymes of oxidative and photosynthetic phosphorylation is closely associated with lipoproteins membranes of mitochondria (tiny round or rod-like structures in the cytoplasm of cells) and chloroplasts (containing chlorophyll organoids cells of plants and animals),
. This close relationship served as a barrier to any kind was a detailed molecular analysis in solution.
A number of researchers engaged in the description of the main structure of the mechanism of oxidative phosphorylation. They learned that in the process of respiration, electrons from various substrates (the substances subjected to the action of the enzyme) to oxygen brings a kind of cascade of enzymes. Synthesis of ATP following the catalytic action of the enzyme complex known as ATP-ase (ATPase). With regard to the chloroplast, the electrons liberated by absorption of light by chlorophyll-mi, progressing through a series of speakers to its ultimate goal - water. Synthesis of ATP is carried out complex ATPase with a molecular structure very reminiscent of the structure of mitochondrial membranes. This study constitutes an important question: how the energy liberated during electron transfer, 'impels' ATPase to synthesize ATFN
. The search for molecular mechanisms based on the theory, . according to which the chain of reactions, . occurring in the process of respiration, . and ATP-ase associated with each having high energy intermediates, . similar to those, . that arise in the course of reactions, . where the catalysts are soluble enzymes,
. M. not specifically studied the mitochondria. He was researching the metabolic transport, which is carried through the membrane tsitoplazmovye bacteria. This topic drew him back when he was a student at Cambridge. In 1958, Mr.. M. and his colleague Jennifer Moyle came to the conclusion that the enzymatic reactions are usually vector. These two scientists have suggested further that the direction of such reactions (albeit in a solution and it remains unclear) should perhaps become clearer when the enzymes are included in the membrane. In fact, the enzymatic complex can be so strong foothold in the membrane, that 'route' reactions to cross this barrier, immediately catalyzes dislocation of the chemical group. They called this process a vector metabolism.
In the period between 1961 and 1966. M. hemiosmoticheskuyu formulated the hypothesis (the name the scientist gave her own) - a radical solution to the problem of bonding energy in the mechanisms of oxidative and photosynthetic phosphorylation. He suggested that the chain of reactions that take place in the process of respiration, is a sequence of successive carriers of hydrogen and electrons. These carriers thus arranged in the inner mitochondrial membrane, that they carry protons (tripeptide) through the membrane. Since the mitochondrial membrane does not allow passive current proton, . in the process of respiration generated electrochemical potential difference for hydrogen ions with an electrically negative internal intercellular substance and the alkaline relevance to the outside intercellular substance,
. Protons on the outer surface tend back in the intracellular substance. It is this flow of protons, which can be compared with the flow of electrons in the battery, and does all the work.
. According hemiosmoticheskoy hypothesis, the existence of the relationship between the chain of chemical reactions in the process of respiration, and ATP-ase not
. This conclusion put forward by M. theory unpopular among many biochemists, some of whom questioned the validity of assumptions scientist. The continuing perception of the radical skepticism of the concept and the ongoing debate around it persuaded M. the need to speak in her defense, proving the validity of its provisions to specific facts. Obtain such data was not easy. For this it was necessary to develop new methods of investigation. In the end, M. Moyle and created a set of quantitative and visual methods. Now with their help was to scrutinize the hypothesis inherent in hemiosmoticheskoy scientific foresight.
. Research work stimulated a debate in the small circle ц¦ц¬ц-ц+ц-цгц¦цёцгц¦ц¬цLц-ц- has played a surprisingly productive as a pilot, and in theoretical terms
. The main question that troubled scientists, was to determine whether the principles hemiosmoticheskoy hypotheses and practical results that can be obtained with its help, the adopted standards. By 1970, Mr.. scales were tipped in favor of established M. concept, in its support by a number of scientists of Great Britain, USA and the USSR.
In 1978. M. was awarded the Nobel Prize in Chemistry 'for his contribution to the understanding of biological energy transfer process, done through the creation hemiosmoticheskoy theory'. In his opening speech on behalf of the Royal Swedish Academy of Sciences Lars Ernster drew attention to the debate, due to MI theory, noting the weight submitted in response to the experimental data. In conclusion, he pointed to a number of practical advantages of M.: 'Chloroplasts, . mitochondria and bacteria can be considered as naturally occurring solar and fuel cells, . and in this capacity, they can serve as a model, . and in the future, . probably, . and 'building blocks' for energy technology. ",
. Since 1964, Mr.
. M. headed the research work in the laboratories of clay in Cornwall. In 1958, Mr.. he married Helen Ffrench. In the couple has three sons and a daughter. Scientists work very much, but it cuts out time and participation in public life. was awarded Lyuissa and Bert Friedman of the New York Academy of Sciences (1976), . Lewis Rozenstila awards for outstanding work in basic medical research, Brandeis University (1977), . Copley medal of the Royal Society of London (1981) and an honorary medal of the Athens Municipal Council (1982),
. He is a member of the Royal Society of London, a foreign member of the U.S. National Academy of Sciences and the Royal Society of Edinburgh. Scientist awarded honorary degrees from the Technical University of Berlin, University of Chicago, East Anglia, Liverpool, Bristol, Edinburgh and many others.