The release of 5-methylene-2-furanone from irradiated DNA catalyzed by cationic polyamines and divalent metal cations.
Release of 5-methylene-2-furanone (5-MF), a characteristic marker of DNA deoxyribose oxidative damage at the C1' position, was observed in significant quantities from X-irradiated DNA. This observation, which held for DNA irradiated either in aqueous solution or as a film, requires postirradiation treatment at 90 degrees C in the presence of polyamines and divalent metal cations at biological pH. The 5-MF product was quantified by using reverse-phase HPLC. The radiation chemical yield of 5-MF comprised more than 30% of the yield of total unaltered base release. Polylysine, spermine and Be(II) showed the strongest catalytic effect on 5-MF release, while Zn(II), Cu(II), Ni(II), putrescine and Mg(II) were substantially less efficient. We have hypothesized that the 5-MF release from irradiated DNA occurs through catalytic decomposition of the 2'-deoxyribonolactone (dL) precursor through two consecutive beta- and delta-phosphate elimination reactions. A stepwise character of the process was indicated by the S-shaped time course of 5-MF accumulation. If dL proves to be the precursor to 5-MF formation, it would then follow that dL is a very important lesion generated in DNA by ionizing radiation.
Roginskaya
Marina
M
Department of Biochemistry and Biophysics, University of Rochester, Rochester, New York 14642, USA.
Bernhard
William A
WA
Marion
Roan T
RT
Razskazovskiy
Yuriy
Y
D002384:Catalysis; D002413:Cations, Divalent / Q000737:chemistry / Q000528:radiation effects; D004247:DNA / Q000737:chemistry* / Q000528:radiation effects*; D004249:DNA Damage / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D005663:Furans / Q000138:chemical synthesis*; D008670:Metals / Q000737:chemistry* / Q000528:radiation effects; D011073:Polyamines / Q000737:chemistry* / Q000528:radiation effects; D000071228:Polyelectrolytes; D011829:Radiation Dosage; D012996:Solutions; D013696:Temperature; D014867:Water / Q000737:chemistry; D014965:X-Rays
D002413:Cations, Divalent; D004247:DNA; D005663:Furans; D008670:Metals; D011073:Polyamines; D000071228:Polyelectrolytes; D012996:Solutions; D014867:Water; C037354:protoanemonin