title: Origin of malondialdehyde from DNA degraded by Fe(II) x bleomycin.
abstract: Ferrous bleomycin is known to break DNA efficiently in vitro in the presence of O2, giving rise to ologonucleotides, bases, and compounds resembling malondialdehyde in their chromogenic reaction with 2-thiobarbituric acid. Chromatography of radiolabeled DNA reaction mixtures resolves three kinds of malondialdehyde-like products, related by sequential conversions. The first chromogenic product is linked to DNA, and its formation does not entail the release of a base. It decomposes readily to the second product, a compound containing the base and deoxyribose carons 1'-3'. Hydrolysis of either product yields the third, which is indistinguishable from authentic malondialdehyde. These findings suggest that the oxygen-dependent cleavage of DNA by Fe(II) x bleomycin can begin with the rupture of the deoxyribose 3'-4'-carbon bond. The initiation of these events is concurrent with the initiation of another mode of DNA degradation, involving the release of free base alone, in a yield similar to that of chromogen.
mesh_terms: D010582:Bacteriophage lambda; D001761:Bleomycin; D055598:Chemical Phenomena; D002621:Chemistry; D004279:DNA, Viral; D004355:Drug Stability; D007501:Iron; D008314:Malonates; D008315:Malondialdehyde; D010084:Oxidation-Reduction; D013053:Spectrophotometry
chemical_list: D004279:DNA, Viral; D008314:Malonates; D001761:Bleomycin; D008315:Malondialdehyde; D007501:Iron