Biochemistry

It has now been established that during the oxidation of 1 mole of acetyl-CoA, 12 moles of ATP are formed in the Krebs cycle, 11 of which result from oxidative phosphorylation and only one from the substrate. One half of the energy generated during the oxidation of organic substances is accumulated in ATP and is involved in biosynthesis, is spent on various needs of the body, the other self is dissipated in the form of heat. It provides constant body temperature (36-37 °C), which is a necessary condition for human life (all the most important processes in the body - gas exchange, the action of enzymes, and therefore the entire metabolism - can be carried out only at a certain temperature) . In many reactions, one residue of inorganic phosphate is cleaved from ATP and ATP is converted to ADP, for example, in the biosynthesis of glucose-6- monophosphate, fructose- 1 ,6-diphosphate. The use of two macroergic bonds of ATP and its conversion to AMP occurs, for example, upon activation of amino acids and fatty acids, the necessary initial stage of their metabolism in cells. Cleavage of the three phosphorus residues and attachment of the substrate to ribose occurs during the biosynthesis of 5- adenosylmethionine. In cells, regulation of the formation of ATP is carried out. So, at lower temperatures, ATP is synthesized in a smaller amount and the oxidation energy is dissipated in the form of heat. Such a process is called free oxidation. It occurs on the surface of mitochondria. Oxidative phosphorylation is stimulated by the presence of ADP and inorganic phosphate. Consequently, with an increase in the consumption of ATP, as a result of which it splits into ADP and NRA 4 , phosphorylation processes intensify and the proportion of energy spent on the formation of heat decreases. ATP cleavage with energy release is catalyzed by the common enzyme adenosine triphosphatase (ATPase). The process takes place at high speed. Instead of cleaved ATP, new molecules of this compound are formed. Therefore, a small amount contained in the tissues is constantly updated. To ensure the synthesis of ATP, it is necessary that energy is constantly generated in the mitochondria due to the oxidation of substances supplied to the body with food. Individual parts of the redox chain are sensitive to various damaging effects. So, the dehydrogenase site is turned off from the transport of hydrogen by barbiturates (in concentrations exceeding therapeutic doses). The process that is particularly sensitive to damaging effects is oxidative phosphorylation, i.e., the energy-intensive ATP formation reaction. 2,4-dinitrophenol , ultrasound , ionizing radiation and other radiation exposure , some antibiotics , carbon monoxide, and hydrocyanic acid can play a negative role in the body . As a result of the influence of these factors, body temperature rises, since all the oxidation energy is converted into heat. 114