[Effect of Pb2+ on spectral characteristics of DNA from fish intestines].
The interaction of Pb2+ and DNA of fish intestines was investigated using absorption spectrum, fluorescence emission spectrum, and electrophoresis. Ultraviolet absorption spectra indicated that with the addition of Pb2+, the DNA generated obvious hypochromic effect, and the absorption peak at 207 nm of DNA was blue-shifted. The fluorescence emission spectra showed that with the addition of Pb2+ , the emission peak of DNA at about 419 nm did not have obvious changes, but the intensity of fluorescence reduced gradually, showing that Pb2+ has quenching effect on the DNA endogenous fluorescence. Pb2+ has 0.8 binding sites to DNA, and the fluorescence quenching of DNA caused by Pb2+ belongs to static quenching. The binding constants of binding sites are 6.08 x 10(4) L x mol(-1) and 2.82 x 10(4) L x mol(-1) from the Lineweaver-Burk plot. The experiments of ultraviolet and fluorescence spectra showed that exogenous Pb2+ could cause some changes to the conformation of DNA, but analysis of electrophoresis proved that exogenous Pb2+ at different concentration did not result in DNA breakage.
Hong
Fa-shui
FS
College of Life Sciences, Suzhou University, Suzhou 215006, China.
Cai
Shu-ming
SM
Liu
Chao
C
Zheng
Lei
L
Lo
Shi-peng
SP
D000465:Algorithms; D000818:Animals; D004247:DNA / Q000737:chemistry*; D004587:Electrophoresis, Agar Gel; D005399:Fishes / Q000378:metabolism; D005453:Fluorescence; D007413:Intestinal Mucosa / Q000378:metabolism*; D007700:Kinetics; D007854:Lead / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry; D013056:Spectrophotometry, Ultraviolet
D007854:Lead; D004247:DNA