title: Bilirubin-Cu(II) complex degrades DNA.
abstract: It has recently been reported that bilirubin forms a complex with Cu(II). In this paper we show that the formation of the complex results in the reduction of Cu(II) to Cu(I) and the redox cycling of the metal gives rise to the formation of reactive oxygen species, particularly hydroxyl radical. The bilirubin-Cu(II) complex causes strand breakage in calf thymus DNA and supercoiled plasmid DNA. Cu(I) was shown to be an essential intermediate in the DNA cleavage reaction by using the Cu(I) specific sequestering reagent neocuproine. Bilirubin-Cu(II) produced hydroxyl radical and the involvement of active oxygen species was established by the inhibition of DNA breakage by various oxygen radical quenchers.
authors.affiliation: Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh 202 002, India.
authors.forename: S F
authors.initials: SF
authors.lastname: Asad
authors.forename: S
authors.initials: S
authors.lastname: Singh
authors.forename: A
authors.initials: A
authors.lastname: Ahmad
authors.forename: S M
authors.initials: SM
authors.lastname: Hadi
mesh_terms: D000818:Animals; D001663:Bilirubin / Q000737:chemistry* / Q000494:pharmacology; D002417:Cattle; D002614:Chelating Agents; D003300:Copper / Q000737:chemistry* / Q000494:pharmacology; D004247:DNA / Q000737:chemistry*; D004249:DNA Damage; D004278:DNA, Superhelical / Q000737:chemistry; D016166:Free Radical Scavengers; D006878:Hydroxides / Q000737:chemistry; D010084:Oxidation-Reduction; D010618:Phenanthrolines; D010957:Plasmids / Q000737:chemistry; D017382:Reactive Oxygen Species; D015719:Single-Strand Specific DNA and RNA Endonucleases / Q000037:antagonists & inhibitors; D013056:Spectrophotometry, Ultraviolet
chemical_list: D002614:Chelating Agents; D004278:DNA, Superhelical; D016166:Free Radical Scavengers; D006878:Hydroxides; D010618:Phenanthrolines; D017382:Reactive Oxygen Species; D003300:Copper; D004247:DNA; C031356:hydroxide ion; C002478:bathocuproine; D015719:Single-Strand Specific DNA and RNA Endonucleases; D001663:Bilirubin