Purines


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Purines

 

a group of natural nitrogenous heterocyclic compounds having a purine-type molecular structure. The structure of purine is

Both in the free state and as constituents of more complex compounds, purines play a key role in the life processes of all organisms. For example, the composition of nucleic acids includes the purine compounds adenine (6-aminopurine) and guanine (2-amino-6-oxypurine) and in some cases includes smaller quantities of methylated adenines, such as 6-methylamino-purine. In ribonucleic acids (RNA), the purine compounds are combined with ribose by a glycoside bond, and in deoxyribonucleic acids (DNA), with deoxyribose by a bond to the nitrogen atom in the 9 position of purine. The content of purines in DNA is equal to that of the pyrimidine bases, while in RNA the amount of purines is usually higher than that of the pyrimi-dines. In nucleic acids, both the purine and pyrimidine compounds effect the coding of hereditary information and its replication during protein biosynthesis.

Nucleotides containing adenine play an important role in bioenergetics; adenosine triphosphate (ATP), for example, is a universal participant in the energy exchange that occurs in living cells. Guanosine triphosphate is necessary for the realization of protein biosynthesis. Cyclic adenosine 3′: 5′-mono-phosphate (cyclic AMP) is an important link in the hormonal regulation mechanism. Purine compounds are also included in the composition of many coenzymes.

Examples of purine compounds are caffeine (contained in coffee and tea), theobromine (contained in the seeds of the cacao tree), hypoxanthine, and xanthine. In higher organisms, the synthesis of purine compounds, in nucleotide form, is effected mainly in the liver; inosine monophosphate serves as a universal intermediate during the final stages of this process. The degradation of purine compounds in various groups of organisms leads to the formation of various final products, such as uric acid, allantoin, and urea.

REFERENCES

Michelson, A. M. Khimiia nukleozidov i nukleotidov. Moscow, 1966. (Translated from English.)
Davidson, J. N. Biokhimiia nukleinovykh kislot. Moscow, 1968. (Translated from English.)
Organicheskaia khimiia nukleinovykh kislot. Moscow, 1970.
Dagley, S., and D. E. Nicholson. Metabolicheskie puti. Moscow, 1973. (Translated from English.)
The Purines: Theory and Experiment. (The Jerusalem Symposia on Quantum Chemistry and Biochemistry, vol. 4.) Jerusalem, 1972.

A. S. ANTONOV

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Other foods it's best to avoid are seafood, meat, spinach, mushrooms, cauliflower and asparagus, as these have moderate amounts of purine.
The intestinal flow of microbial nitrogen was estimated from the amount of purines absorbed (mmol/d), according to the equation:
Instead, the parasite must make purines indirectly, by using an enzyme called purine nucleoside phosphorylase (PNP) to make a purine precursor called hypoxanthine.
To prevent microbial degradation of purines, urine was acidified by 10% H2SO4 to a pH of 2-3.
Patients who have diets high in purines, or who are unable to effectively excrete uric acid, are also more likely to suffer the effects of gout.
The key biochemical manifestation of all of these disorders is a change in the urinary excretion of purines or pyrimidines.
Many purines are poorly soluble in aqueous solutions and may precipitate from urine, forming urinary calculi, if their concentrations exceed the limit of saturation.
Inotek's three platform programs have resulted in 7 novel molecules in various stages of preclinical and clinical development which target: 1) PARP, a fundamental DNA repair and inflammation target; 2) free radicals & oxidants; and 3) purines with a specific focus on adenosine receptors and inosine.
Analysis of purines and pyrimidines in blood, urine, and other physiological fluids.
Uric acid is produced by the breakdown of purines by the body[3], so a low-purine diet will reduce the chances of an attack.
As shown in Table 1, specific transitions were obtained for a large number of purines and pyrimidines, making their separation by HPLC unnecessary.
For the correct diagnosis, it is necessary to have precise and rapid methods for identifying and quantifying purines and pyrimidines in body fluids.