A radioimmunoassay method for 1-beta-D-arabinofuranosyluracil using antibodies directed against 1-beta-D-arabinofuranosylcytosine.
Above pH 7.0 1-beta-D-arabinofuranosyluracil (ara-U) shows marked pH-dependent cross-reactivity with antibodies directed towards 1-beta-D-arabinofuranosylcytosine. Since this peculiar phenomenon has not been observed with other nucleosides and nucleotides thus far tested, it is probably the result of base-catalyzed tautomerism of ara-U to its enolic form which renders it more structurally similar to 1-beta-D-arabinofuranosylcytosine. By performing the radioimmunoassay at both pH 6.2 and 8.6 we could determine 1-beta-D-arabinofuranosylcytosine and ara-U simultaneously. This method for ara-U assay is simple, fairly reliable, and applicable to blood level studies.
D000818:Animals; D000906:Antibodies; D001086:Arabinofuranosyluracil / Q000032:analysis* / Q000097:blood / Q000378:metabolism; D055598:Chemical Phenomena; D002621:Chemistry; D003429:Cross Reactions; D003561:Cytarabine / Q000031:analogs & derivatives / Q000032:analysis / Q000097:blood / Q000276:immunology* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D051379:Mice; D009705:Nucleosides / Q000378:metabolism; D009711:Nucleotides / Q000378:metabolism; D011741:Pyrimidine Nucleosides / Q000032:analysis*; D011863:Radioimmunoassay / Q000379:methods*
D000906:Antibodies; D009705:Nucleosides; D009711:Nucleotides; D011741:Pyrimidine Nucleosides; D003561:Cytarabine; D001086:Arabinofuranosyluracil