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.

Targeting an Artificial Metal Nuclease to DNA by a Simple Chemical Modification and Its Drastic Effect on Catalysis

“…In order to evaluate the kinetic profile of cleavage of complex 1 (Figure ), a pseudo-Michaelis–Menten analysis was performed and the obtained parameters are shown in Table . This indicates that complex 1 cleaves DNA with a k cat value of 0.89 h –1 and an enhancement over the uncatalyzed DNA cleavage reaction of 2.4 × 10 7 times; these data are consistent with the literature. − …”

Binary and ternary new water soluble copper(II) complexes of l -tyrosine and substituted 1,10-phenanthrolines: Effect of substitution on DNA interactions and cytotoxicities

“…One of the earlier studies in EB fluorescence displacement study, the K app value for [Cu(phen) 2 ](ClO 4 ) 2 was found to be 6.67 Â 10 5 M À1 [76]. Yang et al [68], K sv value of ternary copper(II) complex -[Cu-phen-tyr](H 2 O)](ClO 4 ) -was calculated to be 2.88 Â 10 3 M À1 (with gallic acid) and 0.61 Â 10 3 M À1 (without gallic acid). As another example of the fluorescence intercalator displacement assay, the synchronous fluorescence spectroscopy was applied to investigate the competitive interaction of DNA with the bis(1,10-phenanthroline)copper(II) complex cation ([Cu(phen) 2 ] 2+ ) and a fluorescence probe, neutral red dye.…”

Heat treatment of quinoa (Chenopodium quinoa Willd.) albumin: Effect on structural, functional, and in vitro digestion properties

“…Proteins are mainly composed of AAs that act as auxiliary ligands ( 34 ). The AAs found in QA were compared to the FAO/WHO models of reference, as shown in Table 1 .…”