title: In vivo synthesis of 6-azauridine 5'-triphosphate and incorporation of 6-azauridine into RNA of germinating wheat embryonic axes.
abstract: The cytostatic effect of 6-azauridine on cell growth is generally regarded to be a consequence of the inhibition of de novo pyrimidine biosynthesis by the metabolite, 6-azauridine 5'-monophosphate. We show here that wheat embryonic axes further metabolize 6-azauridine to the 5'-triphosphate and incorporate the analogue into RNA, thus offering an alternative mechanism for growth inhibition. At a level of 6-azauridine required to maximally inhibit UTP biosynthesis, the ratio of 6-azaUTP to UTP is about 2:1 and substitution of 6-azauridine for uridine in new RNA is on the order of 1 in 18. The new metabolites of 6-azauridine are identified by high pressure and thin layer chromatography coupled with enzyme treatments.
mesh_terms: D001380:Azauridine / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000378:metabolism* / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D010944:Plants / Q000378:metabolism*; D012313:RNA / Q000096:biosynthesis*; D012265:Ribonucleotides / Q000302:isolation & purification; D014908:Triticum / Q000378:metabolism; D014500:Uracil Nucleotides / Q000096:biosynthesis*; D014544:Uridine Triphosphate / Q000031:analogs & derivatives / Q000096:biosynthesis*
chemical_list: D012265:Ribonucleotides; D014500:Uracil Nucleotides; C026640:6-azauridine 5'-triphosphate; D012313:RNA; D001380:Azauridine; D014544:Uridine Triphosphate