Adenosinephosphoric Acids

Adenosinephosphoric Acids 

nucleotides; mono-, di-, and triphosphate esters of adenosine containing adenine, the carbohydrate ribose, and one (AMP), two (ADP), or three (ATP) phosphoric acid residues. Adenosinephosphoric acids occur in all organisms (from microbes and plants to man) and play a most important part in metabolism and energy metabolism, since the addition of phosphate groups to AMP is accompanied by accumulation of energy (ADP and ATP are energy-rich compounds), while their dissociation is accompanied by release of energy, which is used for various vital processes. In the cells, there is continuous interconversion of ATP, ADP, and AMP. Adenosinemonophosphoric acid (AMP, adenylic acid) has one phosphoric acid residue. Its molecular weight is 347.23. Depending on the point of attachment of the phosphoric acid residue to the ribose, 5’-AMP (“muscle” AMP), 3’-AMP (“yeast” AMP), and 2’-AMP are distinguished. AMP is a component of the nucleic acids and enters into the composition of many enzymes. The main derivatives of AMP are cyclic AMP, which activates the enzyme phosphorylase, and ATP. Adenosinediphosphoric acid (ADP) has two phosphoric acid residues. Its molecular weight is 427.22. ADP is formed from ATP by the enzymatic cleavage of a phosphoric acid residue. It plays an important part in energy metabolism and oxidative phosphorylation. Adenosinetriphosphoric acid (ATP, adenylpyrophos-phoric acid) has three phosphoric acid residues. Its molecular weight is 507.21. It is a substrate for the biosynthesis of nucleic acids. One or two terminal phosphate groups easily split off from the ATP under the influence of adenosine-triphosphatase enzymes; ADP or AMP is formed and energy is released (30–40 kilojoules, or 7–10 kilocalories per phosphate group). The addition of phosphoric acid residues to AMP and ADP is accompanied by energy storage in the ATP formed. During the transfer of the readily split-off high energy-rich (macroergic) phosphate groups from the ATP to other substances, this energy is transmitted to the latter or expended for muscular contraction, neural excitation, glandular secretion, the biosynthesis of proteins and other substances, and so on. Resynthesis of ATP occurs during oxidative or photosynthetic phosphorylation, or phosphorylation coupled with glycolysis, or is connected with other high-energy processes.

Solutions of the disodium and monocalcium salts of adenosine triphosphoic acid are injected for therapeutic purposes in cases of muscular dystrophy and spasms of the cardiac and peripheral blood vessels. ATP preparations are contraindicated in cases of recent myocardial infarctions and inflammatory pulmonary diseases.

REFERENCES

Ivanov, I. I., and V. A. Iur’ev. Biokhimiia i patobiokhimiia myshts. Leningrad, 1961.
Zbarskii, B. I., I. I. Ivanov, and S. R. Mardashev. Biologich. khimiia, 4th ed. Leningrad, 1965.
Lehninger, A. Mitokhondriia. Moscow, 1966. (Translated from English.)
Racker, E. Bioenergetich. mekhanizmy. Moscow, 1967. (Translated from English.)

I. B. ZBARSKII