resulting consumption of inorganic phosphate brings about a decrease in the intensity of glycolysis, and inversely. The Pasteur Effect is therefore an example of an autoregulation of all the complex phenomena of the priming reactions. Another factor in the regulation of the intensity of respiratory metabolism is operative in the mitochondria, and this is the supply to the interior of the mitochondria of phosphate acceptors such as AMP and ADP.To the autoregulatory processes of this type can be added the action of specialized regulators such as the hormones which have been developed by organisms in the course of biochemical evolution.
III. THE GENETIC CONTROL OF THE RELATIVE RATES OF ENZYMATIC REACTIONS
Although it is true that the cells of various organisms all possess meta- bolic systems having the general features described in part three of this book, each species has certain specific peculiarities in the macromolecules of which it is formed, the enzymes included.Heredity transmits to the descendants of an organism the specific type of control of the relative rates of the diverse enzymic reactions which take place in each of its cells. It has now been well established that an alteration in a given gene can bring about definite biochemical changes manifested by the disappearance of one constituent in the organism, or the appearance of a new one, or by an increase or a decrease in the amount of a compound or of a group of compounds. New stationary states are set up resulting from changes in the speed of this or that metabolic process. For example, in a given organism consider the concentration of a substance A. In the station- ary state in the organism, the concentration of A remains approximately constant as a result of an equilibrium between the production process and its transformation. If the rate of production decreases, even slightly, and if the rate of transformation does not alter, then substance A will disappear.Although the biochemical phenotype, like phenotypes in general, is a product of the interaction of the internal milieu of the cell, and its genotype, the means by which the latter influences the system of macromolecules in the cell and in particular the enzymes still remains a mystery.
REFERENCES
HOLZER ( 1953). "Über Fermentketten und ihre Bedeutung für die Regulation des Kohlenhydratstoffwechsels in lebenden Zellen". Biologie und Wirkung der Fermente. 4. Colloquium der Ges. für physiol. Chem., Springer, Berlin- Göttingen-Heidelberg. 89-112.
LARDY H. A. ( 1952). "The role of phosphate in metabolic control mechanisms". The Biology of Phosphorus, WOLTERINK L. F. (Editor) Michigan State College Press, 131-147.
POTTER VAN R. ( 1949). "The control of metabolism". Respiratory Enzymes, LARDY H. A. (Editor) Burgess, Minneapolis, revised ed., 264-272.
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Publication Information: Book Title: Unity and Diversity in Biochemistry: An Introduction to Chemical Biology. Contributors: Marcel Florkin - author, T. Wood - transltr. Publisher: Pergamon Press. Place of Publication: Oxford. Publication Year: 1960. Page Number: 286.
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