Purine nucleoside phosphorylase (EC 2.4.2.1; purine nucleoside:orthophosphate ribosyltransferase) from fresh human erythrocytes has been purified to homogeneity in two steps with an overall yield of 56%. The purification involves DEAE-Sephadex chromatography followed by affinity chromatography on a column of Sepharose/formycin B. This scheme is suitable for purification of the phosphorylase fro...

A 30 base pair parallel-stranded (ps) duplex ps-L1.L2 composed of two adjoined purine-purine and purine-pyrimidine sequence blocks has been characterized thermodynamically and spectroscopically. The 5'-terminal 15 residues in both strands ('left-half') consisted of the alternating d(GA)7G sequence that forms a ps homoduplex secondary structure stabilized by d(G.G) and d(A.A) base pairs. The 3'-...

Marine mammals are exposed to ischemia/reperfusion and hypoxia/reoxygenation during diving. During oxygen deprivation, adenosine triphosphate (ATP) breakdown implies purine metabolite accumulation, which in humans is associated with pathological conditions. Purine recycling in seals increases in response to prolonged fasting and ischemia. Concentrations of metabolites and activities of key enzy...

Riboswitches are highly structured RNA elements that control the expression of many bacterial genes by binding directly to small metabolite molecules with high specificity and affinity. In Bacillus subtilis, two classes of riboswitches have been described that discriminate between guanine and adenine despite an extremely high degree of homology both in their primary and secondary structure. We ...

We examined more than 700 DNA sequences (full length chromosomes and plasmids) for stretches of purines (R) or pyrimidines (Y) and alternating YR stretches; such regions will likely adopt structures which are different from the canonical B-form. Since one turn of the DNA helix is roughly 10 bp, we measured the fraction of each genome which contains purine (or pyrimidine) tracts of lengths of 10...

The capacity of intact cells of roots excised from summer squash plants (Cucurbita pepo L. cv Early Prolific Straightneck) to synthesize purine nucleotides de novo was investigated. Evidence that purine nucleotides are synthesized de novo included: (a) demonstration of the incorporation of [1-(14)C]glycine, [2-(14)C]glycine, NaH(14)CO(3), and H(14)COONa into total adenine nucleotides; (b) obser...

The effect of repeated oral administration of ATP on purine transport and metabolism was investigated in rats. An increased ability of the gut to capture intraluminal purine nucleosides and to export ATP and nucleosides toward portal bloodstream was observed in rats after 30 days of treatment with 5 mg/kg/day ATP. This was accompanied in erythrocytes by an increased transport of adenosine rapid...

The single nucleoside transport function of mouse S49 lymphoblasts also transports purine bases (B. Aronow and B. Ullman, J. Biol. Chem. 261:2014-2019, 1986). This transport of purine bases by S49 cells is sensitive to inhibition by dipyridamole (DPA) and 4-nitrobenzylthioinosine, two potent inhibitors of nucleoside transport. Therefore, wild-type S49 cells cannot salvage low hypoxanthine conce...

In Taiwan, adult hyperuricemia affects as many 1 in 4 males and 6 females, who are predominantly young adults aged 19–45. this study, lactic acid bacteria (LAB) with tolerance, bile salt tolerance high affinity to intestinal cells were extracted from the side products of alcohol fermentation (distillers’ grains). These evaluated for their ability lower uric levels. Qualitative identification qu...

Purine nucleoside phosphorylase (EC 2.4.2.1) from Bacillus cereus T was examined at hourly intervals during growth and sporulation. The enzyme has maximal activity in extracts prepared from cells during stages I and II. The activity during exponential growth is only 6.6% of the maximum and that in free spores is only 3.3%. Conservation of the purine nucleoside phosphorylase during sporulation i...