title: [Double modification of cytidine residues in DNA].
abstract: The reaction of O-beta-diethylaminoethylhydroxylamine (O-beta-HA) with cytidine was studied and its mechanism was shown to be analogous to that of the reaction of hydroxylamine of O-methylhydroxylamine with cytidine. In experiments involving reaction of denatured DNA with O-beta-HA., Sephadex G-15 columns were used for the quantitative separation of normal and modified nucleosides after enzymatic hydrolysis of modified DNA by exonuclease A5 followed by alkaline phosphatase treatment. DNA cytidine residues of free cytidine with O-beta-HA. Modified cytidines can form complex with phosphotungstic acid (PTA). It was shown that one mole of PTA was bound per one mole of modified cytidine either in DNA or in free state. Electron microscopic examination of denatured DNA molecules modified by O-beta-HA and reacted with PTA revealed linear arrays of electron-scattering spots which presumably correspond to PTA molecules complexed with modified cytidine in DNA chains.
mesh_terms: D000469:Alkaline Phosphatase; D003562:Cytidine; D004247:DNA; D003851:Deoxyribonucleases; D005092:Exonucleases; D006898:Hydroxylamines; D009690:Nucleic Acid Conformation; D013056:Spectrophotometry, Ultraviolet
chemical_list: D006898:Hydroxylamines; D003562:Cytidine; D004247:DNA; D003851:Deoxyribonucleases; D005092:Exonucleases; D000469:Alkaline Phosphatase
vernacular_title: Dvoĭnaia modifikatsiia tsitidina v DNK.