title: Inhibition of L-DOPA-Cu(II)-mediated DNA cleavage by bilirubin.
abstract: It has been proposed that considerable DNA damage may be caused by endogenous metabolites produced during the body's normal metabolic processes. We have previously shown that L-DOPA, in the presence of Cu(II), leads to oxidative DNA breakage in vitro. Bilirubin is a degradation product of heme and is considered to possess antioxidant properties. In this paper we report that bilirubin inhibits L-DOPA-Cu(II)-mediated DNA cleavage to an appreciable extent of 50% at a concentration of 50 microM. Bilirubin was also shown to directly quench the generation of hydroxyl radicals by L-DOPA-Cu(II) to an extent of 30% at a concentration of 20 microM. The results support the putative antioxidant role of bilirubin in higher primates.
authors.affiliation: Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligath (U. P.) 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 / Q000494:pharmacology*; D002417:Cattle; D003300:Copper / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D004247:DNA / Q000187:drug effects; D004249:DNA Damage / Q000187:drug effects*; D004278:DNA, Superhelical / Q000187:drug effects; D004347:Drug Interactions; D017665:Hydroxyl Radical / Q000378:metabolism; D007980:Levodopa / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D010957:Plasmids / Q000235:genetics
chemical_list: D004278:DNA, Superhelical; D017665:Hydroxyl Radical; D007980:Levodopa; D003300:Copper; D004247:DNA; D001663:Bilirubin