FUdR is readily phosphorolyzed by thymidine phosphorylase (EC 2.4.2.4) purified from Escherichia coli (22), and it also can be cleaved by uridine phosphorylase (EC 2.4.2.3) purified from Ehrlich ascite tumor (21). It has been suggested that this breakdown may be a reason for the limited therapeutic effect of FUdR, and various attempts to find conditions that prevent phosphorolysis of FUdR have ...

The authors report results from computational studies of the interaction of low-energy electrons with the purine bases of DNA, adenine and guanine, as well as with the associated nucleosides, deoxyadenosine and deoxyguanosine, and the nucleotide deoxyadenosine monophosphate. Their calculations focus on the characterization of the pi* shape resonances associated with the bases and also provide g...

A family of artificial nucleosides has been developed by applying the Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition. Starting from 2-deoxy-β-D-glycosyl azide as a common precursor, three bidentate nucleosides have been synthesized. The 1,2,3-triazole involved in all three nucleobases is complemented by 1,2,4-triazole (TriTri), pyrazole (TriPyr), or pyridine (TriPy). Molecular structures of ...

Nucleoside transporters play key roles in the physiology of nucleosides and nucleobases in mammals and also contribute to the pharmacological actions produced by their analogs. Several mammalian nucleoside transporters have been identified at the molecular level. The aim of this study was to examine the expression of the major nucleoside transporter isoforms in the mouse testis and ovary. Equil...

Disaccharide nucleosides are an important class of natural compounds that have a variety of biological activities. In this study, we report on the synthesis of disaccharide nucleosides utilizing the temporary protection of the 2',3'-cis-diol of ribonucleosides, such as adenosine, guanosine, uridine, 5-metyluridine, 5-fluorouridine and cytidine, by a boronic ester. The temporary protection of th...

An adenosine-assimilating bacterium, Klebsiella sp. strain LF1202, inducibly formed a novel nucleoside phosphorylase which acted on both purine and pyrimidine nucleosides when the cells were cultured in medium containing adenosine as a sole source of carbon and nitrogen. The enzyme was purified (approximately 83-fold, with a 17% activity yield) to the homogeneous state by polyacrylamide gel ele...

Synthetic modification of nucleoside structures provides access to molecules of interest as pharmaceuticals, biochemical probes, and models to study diseases. Covalent modification of the purine and pyrimidine bases is an important strategy for the synthesis of these adducts. Palladium-catalyzed cross-coupling is a powerful method to attach groups to the base heterocycles through the formation ...

Prevention of nucleoside loss in bile is physiologically desirable because hepatocytes are the main source of nucleosides for animal cells which lack de novo nucleoside biosynthesis. We have demonstrated a Na+ gradient-energized, concentrative nucleoside transport system in canalicular membrane vesicles (CMV) from rat liver by studying [3H]adenosine uptake using a rapid filtration technique. Th...