Inhibition of L-DOPA-Cu(II)-mediated DNA cleavage by bilirubin.
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.
Asad
S F
SF
Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligath (U. P.) 202 002, India.
Singh
S
S
Ahmad
A
A
Hadi
S M
SM
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
D004278:DNA, Superhelical; D017665:Hydroxyl Radical; D007980:Levodopa; D003300:Copper; D004247:DNA; D001663:Bilirubin