Formation of 8-hydroxyguanine and 2,6-diamino-4-hydroxy-5-formamidopyrimidine in DNA by riboflavin mediated photosensitization.
Calf thymus DNA was photoirradiated in the presence of riboflavin. Altered bases were detected and quantified by the GC/MS-SIM method after hydrolysis and derivatization of DNA. Seven types of modified purine bases were detected in control DNA. Among them, the yields of 8-OH-Gua and FapyGua increased significantly in DNA photo-irradiated with riboflavin, whereas the yields of xanthine, 8-OH-Ade, 2-OH-Ade, FapyAde and hypoxanthine were not affected. A dose dependent increase in the formation of 8-OH-Gua was observed with increasing riboflavin concentration for 30 min irradiation. On the other hand, FapyGua reached plateau at 10 micrograms/ml of riboflavin for 30 min irradiation. Our results indicate that guanine moiety in DNA is the most susceptible to riboflavin mediated photosensitization.
Mori
T
T
Research Institute for Advanced Science and Technology, Osaka Prefecture University, Japan. morit@riast.osakafu-u.ac.jp
Tano
K
K
Takimoto
K
K
Utsumi
H
H
D000818:Animals; D002417:Cattle; D004247:DNA / Q000737:chemistry / Q000528:radiation effects*; D008401:Gas Chromatography-Mass Spectrometry; D006147:Guanine / Q000031:analogs & derivatives* / Q000032:analysis; D008027:Light; D017319:Photosensitizing Agents; D011743:Pyrimidines / Q000032:analysis*; D012256:Riboflavin
D017319:Photosensitizing Agents; D011743:Pyrimidines; C071023:2,6-diamino-4-hydroxy-5-formamidopyrimidine; C024829:8-hydroxyguanine; D006147:Guanine; D004247:DNA; D012256:Riboflavin