title: Direct measurement of pyrimidine C6-hydrate stability.
abstract: Pyrimidine C6-hydrates are produced via UV-irradiation and undergo dehydration upon standing. The stability of these compounds has a direct bearing on their genotoxicity. The rate constants for elimination from 5'-benzyoylated derivatives of 5,6-dihydro-5-hydroxythymidine (6) and 5,6-dihydro-5-hydroxy-2'-deoxyuridine (9) were measured directly via HPLC. The rate constants for dehydration increase from pH 6.0 to 8.0. The half-lives for 6 and 9 at pH 7.4 and 37 degrees C are 46.5 and 24.4h, respectively. Deglycosylation is not observed, even upon heating at 90 degrees C. These observations reinforce proposals that pyrimidine hydrates are sufficiently long-lived that they can exert significant effects on biological systems.
authors.affiliation: Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: K
authors.initials: K
authors.lastname: Nolan Carter
authors.forename: M M
authors.initials: MM
authors.lastname: Greenberg
mesh_terms: D004249:DNA Damage; D004260:DNA Repair; D006031:Glycosylation; D006863:Hydrogen-Ion Concentration; D006900:Hydroxylation; D007700:Kinetics; D011743:Pyrimidines / Q000737:chemistry / Q000378:metabolism*; D013936:Thymidine / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D014529:Uridine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism
chemical_list: D011743:Pyrimidines; C012360:6-hydroxy-5,6-dihydrouridine; C029950:5,6-dihydro-6-hydroxythymidine; D013936:Thymidine; D014529:Uridine