Study Of Nucleotide Metabolism Research Articles

Study of nucleotide metabolism and its interrelation with pro-oxidant and antioxidant systems in people of different ages

The interrelation of purine nucleotides with the antioxidant system in blood plasma and erythrocytes with respect to age, as well as the contribution of key enzymes of the purine decomposition to the formation of reactive oxygen species, were studied. Fifty conditionally healthy people aged 40–79 years (50 persons) were examined. All indicators of the pro-oxidant system of blood plasma were shown to increase with age. Statistically significant interrelations between the studied parameters in the blood plasma and age of the examined persons were found. Relationships between glutathione peroxidase and adenosine deaminase/xanthine oxidase, adenosine deaminase and xanthine oxidase were also demonstrated. A significant increase in the content of products of oxidative modification of proteins in plasma and erythrocytes was observed with aging. It was shown that key enzymes of antioxidant protection, i.e., superoxide dismutase and glutathione peroxidase, were reduced in blood plasma and erythrocytes with age. The results indicate that an imbalance in the antioxidant system occurs with age in blood plasma and erythrocytes, and this process contributes to the development of pathological conditions by increasing oxidative stress, which is especially pronounced with age.

Inborn Errors in Purine Metabolism: Role of 5′-Nucleotidases and Their Involvement in the Etiology of Neurological Impairments

A number of scientists have been involved for decades in the study of nucleotide metabolism in different species of living beings. We are, therefore, aware of the relevant roles of purine compounds and of the many different ways in which these compounds influence cell life, acting both inside and outside the cells. Nevertheless, the consequences of an alteration (lack of expression, or hypo- or hyperexpression) in the activity of enzymes involved in the metabolism of these compounds are sometimes surprising, and far from being mechanistically explained. Alterations in enzyme activities involved in nucleotide metabolism are frequently associated with syndromes characterized by two different types of problems – one, metabolic, which is expected and can be easily explained, and the second, neurological and behavioral. Neurological and behavioral impairments are more difficult to explain and show a very high degree of individual variability. The molecular bases of the neurological impairment linked to purine metabolism disorders have been extensively studied. These studies have generated a lot of hypotheses but very few certainties. In this short review, neurological and behavioral symptoms linked to the dysfunction of some enzymes involved in purine synthesis, catabolism, and salvage will be briefly described, with particular attention to their metabolic and regulatory consequences. Finally, attention will be focused on the 5′-nucleotidase family members and on their involvement in the regulation of purine and pyrimidine metabolism.

Fast atom bombardment tandem mass spectrometry in the identification of isomeric ribomononucleotides

Analysis of isomeric ribomononucleotides by positive-ion fast atom bombardment tandem mass spectrometry is described. Daughter ion spectra generated by collision-induced dissociation—mass-analysed ion kinetic energy scanning on a sector instrument are compared with daughter ion spectra from a triple quadrupole mass spectrometer, and criteria are established for the differentiation of the 2′-, 3′- and 5′-monophosphate isomers of adenosine, guanosine and cytosine, based on their characteristic fragmentation patterns. The value of tandem mass spectrometry in the identification of nucleotides extracted from biological systems and isolated by high-performance liquid chromatography and in the study of nucleotide metabolism is discussed.

Effects of ischemia on the concentration of adenine nucleotides in the kidney of anesthetized dogs.

SummaryIschemia causes a rapid decline in the concentration of ATP in the kidney cortex of anesthetized dogs. Within 8 sec of ischemia distribution of adenine nucleotides is determined by activity of adenylate kinase. Nucleotide metabolism of the cortex of dog is distinguished from that of rat by the observation that concentrations are lower and by the evidence of activity of adenylate kinase. We estimate that blood-flow dependent ATP turnover in the cortex is 27% of that calculated on the basis of renal O2 consumption. The medulla, in contrast to the cortex, maintains its ATP concentration during 60 sec of interruption of blood flow. Studies of nucleotide metabolism in the kidney must include consideration of differences in adenylate kinase activity between cortex and medulla and between different mammalian species.