title: Copper (II) complex of 1,10-phenanthroline and L-tyrosine with DNA oxidative cleavage activity in the gallic acid.
abstract: Copper (II) complex of formulation [Cu-Phen-Tyr](H(2)O)](ClO(4)) (Phen = 1,10-phenanthroline, L: -Tyr = L: -tyrosine), has been prepared, and their induced DNA oxidative cleavage activity studied. The complex binds to DNA by intercalation, as deduced from the absorption and fluorescence spectral data. Scatchard plots constructed from the absorption titration data gave binding constant 2.44 × 10(4) M(-1) of base pairs. Extensive hypochromism, broadening, and red shifts in the absorption spectra were observed. Upon binding to DNA, the fluorescence from the DNA--ethidium bromide system was efficiently quenched by the copper (II) complex. Stern--Volmer quenching constant 0.61 × 10(3) M(-1) obtained from the linear quenching plots. [Cu-Phen-Tyr] complex efficiently cleave the supercoiled DNA to its nicked circular form with gallic acid as biological reductant at appropriate complex concentration. The gallic acid as reductant could observably improve copper (II) complex to DNA damage. The pseudo-Michaelis-Menten kinetic parameters (k(cat), K(M)) were calculated to be 1.32 h(-1) and 5.46 × 10(-5) M for [Cu-Phen-Tyr] complex. Mechanistic studies reveal the involvement of superoxide anions and hydroxyl radical (HO(·)) as the reactive species under an aerobic medium.
authors.affiliation: Anhui Key Laboratory of Chemo-Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, People's Republic of China. yzhoushe@mail.ahnu.edu.cn
authors.forename: Zhousheng
authors.initials: Z
authors.lastname: Yang
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.forename: Geng
authors.initials: G
authors.lastname: Yang
mesh_terms: D003300:Copper / Q000737:chemistry*; D053837:DNA Cleavage / Q000187:drug effects; D004563:Electrochemistry; D004587:Electrophoresis, Agar Gel; D005707:Gallic Acid / Q000737:chemistry*; D007700:Kinetics; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry / Q000494:pharmacology*; D010084:Oxidation-Reduction; D010618:Phenanthrolines / Q000737:chemistry*; D010957:Plasmids / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D014443:Tyrosine / Q000737:chemistry*
chemical_list: D009942:Organometallic Compounds; D010618:Phenanthrolines; D014443:Tyrosine; D005707:Gallic Acid; D003300:Copper; C025205:1,10-phenanthroline