Purines


Also found in: Dictionary, Thesaurus, Medical.

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

References in periodicals archive ?
Enjoy foods low in purine, such as cauliflower, peas, beans, sweet potatoes and low-fat dairy.
In regard to ruminal nucleic acid bases, the variation coefficient of uracil bases was highest but that of purine was lowest.
The reaction of ECF towards purines and pyrimidines; G, A, C, T and U was examined to form their derivatives and their elution from GC column was investigated reaction is shown in (Fig.
Estimation of microbial protein supply to sheep and cattle based on urinary excretion of purine derivatives - an overview of technical details.
By inhibiting PNP, the drug BCX4945 kills the parasites by starving them of the purines they need to survive.
To prevent microbial degradation of purines, urine was acidified by 10% H2SO4 to a pH of 2-3.
Without the purines that trigger urate stone formation, even susceptible dogs can lead normal lives.
Cerca de 1999, el directorio de Agrosuper nos dio una orden", recuerda Carlos Andres Vives, subgerente de asuntos corporativos de la empresa, mientras maneja una camioneta a otro centro de tratamiento de purines.
Los purines de cerdo presentan caracteristicas que determinan que sean grandes contaminantes, afectando al medio ambiente y al ser humano, producto de un manejo y tratamiento inadecuado.
Electrophysiological recordings from KD-fed rats demonstrated changes in synaptic transmission as well as the influence of purines on synaptic transmission that were consistent with the alterations in adenylate energy charge and purine metabolism observed neurochemically.
Uric acid occurs as a normal byproduct of purines, compounds found naturally in high-protein foods.
Purines and pyrimidines serve as precursor molecules for DNA and RNA, as energy storage depots, as metabolic regulators, and as intermediates in biosynthetic pathways.