BACKGROUND Purine nucleotides are essential metabolites for living organisms because they are involved in many important processes, such as nucleic acid synthesis, energy supply, and biosynthesis of several amino acids and riboflavin. Owing to the pivotal roles of purines in cell physiology, the pool of intracellular purine nucleotides must be maintained under strict control, and hence the de n...

Background: Cardiovascular diseases are global problems. They are causes of death in about 43% of people worldwide and may become the most widespread reason of death by 2020. The prognosis is directly dependent to immediate diagnosis and on time treatment. Introduction of new biochemical markers as the early diagnosis of complications after coronary revascularization is very important in this p...

Exogenous purines are known to suppress purine synthesis de novo in bacteria (2-4), HeLa and L cells (5), and ascites cells (6) growing in culture. High levels of purines, especially adenine, inhibit accumulation of late purine precursors in the media of bacteria with blocks in the pathway of purine synthesis (2, 3), or of formylglycinamide ribonucleotide in Ehrlich ascites cells grown in the p...

In a previous study (l), evidence was presented to show that in a mutant of Neurospora the whole carbon skeleton of cytidine is incorporated with equal effectiveness into the pyrimidine nucleosides of ribonucleic acid and deoxyribonucleic acid. In this article a comparable experiment is described in which uniformly labeled Cr4-adenosine was fed to an adenine-requiring mutant grown in the presen...

Five multiparous, ruminally cannulated Holstein cows (two lactating and three dry) weighing (X +/- SD) 667 +/- 35 kg were used to study the effect of abomasal purine infusion on the excretion of purine derivatives. Cows were fed corn silage four times daily at 90% of ad libitum intake (X = 9.16 kg of dry matter/d). Purines were infused into the abomasum as brewer's yeast suspensions in five inc...

Rates of purine synthesis de novo, as measured by the incorporation of [14C]formate into newly synthesized purines, have been determined in cultured human fibroblasts derived from normal individuals and from patients deficient in adenosine deaminase, purine nucleoside phosphorylase, or hypoxanthine phosphoribosyltransferase, three consecutive enzymes of the purine salvage pathway. All four type...

An animal model was used to determine the basis for the increase in purine biosynthesis that results from hepatic depletion of purine nucleotides, such as seen in patients with type I glycogen storage disease or following fructose administration. Mice were injected intravenously with glucose or fructose, 2.5 mg/g of body weight, and the animals were killed at 0, 3, and 30 min following carbohyd...

Intracellular Toxoplasma gondii grown in human foreskin fibroblast cells transported nitrobenzylthioinosine [NBMPR; 6-[(4-nitrobenzyl)mercapto]-9-beta-D-ribofuranosylpurine], an inhibitor of nucleoside transport in mammalian cells, as well as the nonphysiological beta-L-enantiomers of purine nucleosides, beta-L-adenosine, beta-L-deoxyadenosine, and beta-L-guanosine. The beta-L-pyrimidine nucleo...