ABSTRACT
The interaction between Fe3(CO)12 and DNA was investigated by absorption and spectra, fluorescence spectra. The absorption of EB-DNA system in the presence of Fe3 (CO)12 showed that Fe3(CO)12 could partly sustain the place of EB. The result of fluorescence spectra suggested that Fe3(CO)12 could enhance the fluorescence intensity of DNA sharply. All the experimental results indicated that the intercalative binding mode was the major model for the interaction of Fe3(CO)12 cluster complex with DNA.
Subject(s)
DNA/chemistry , Ferric Compounds/chemistry , Ethidium/chemistry , Nucleic Acid Conformation , Spectrometry, FluorescenceABSTRACT
The mechanism of the interaction between hydrazide-podophyllic (HDPP) metal (Me) complexes and calf thymus (ct) DNA in Tris buffer (pH 7.08) was studied by viscosity measurements, electronic absorption, gel electrophoresis, and ethidium bromide (EB) fluorescence spectroscopy. The results from varied experiments show that the intensity of the maximal absorption peaks from absorption spectra is weakened in the presence of DNA compared with that in the absence of DNA. Meanwhile, DNA can remarkably quench the emission intensity of the complex Me-HDPP system. The Me-HDPP complexes can increase the viscosity of ct DNA slightly and catalyze the cleavage of super coiled pBR322 DNA to the nicked form. The complexes of Ni-HDPP and Co-HDPP can be bound to ct DNA mainly by interaction, while the partial interaction of Zn-HDPP and ct DNA is the major modes. The binding constant of Me-HDPP complexes with ct DNA was determined.
Subject(s)
DNA/chemistry , DNA/metabolism , DNA, Superhelical/chemistry , Hydrazines/chemistry , Plasmids/chemistry , Podophyllin/chemistry , Spectrometry, FluorescenceABSTRACT
The interaction between the metal complex of hydrazide of podophyllic acid and calf thymus (CT) DNA was studied by using absorption spectra, fluorescence spectra and DNA heat denaturation. It was found that the intensity of the maximal absorption peaks from absorption spectra is weakened in the presence of the metal complex of hydrazide of podophyllic acid compared with that in the absence of the metal complex. All the experimental results show that the intercalation mode was proved to exist between HDPP-Ni complexes and CT DNA.
Subject(s)
Anti-Bacterial Agents/chemistry , DNA/chemistry , Podophyllotoxin/analogs & derivatives , Animals , Cattle , Podophyllotoxin/chemistry , Spectrophotometry, UltravioletABSTRACT
Complexes of chitosan with Cu(II) were prepared by adding Cu(OAc)2.H2O to chitosan solution. IR, UV, elemental analysis, and thermal weight analysis were used to characterize the complex. The results showed that there were coordinate bands formed. H2O2 was used to degrade chitosan-Cu(II) complex, and the molecular distribution of degraded products was investigated. The result suggested that the chitosan could be degraded rapidly, the degradation started from higher molecular weight range, and the molecular weight distribution of oligosaccharides was much more narrow than that of degraded products with usual methods, such as hydrolysis acidic and oxidizing conditions. The index of molecular weight distribution changed with the average degradability. When exceeding 10 oligosaccharides, the smaller the DP, the smaller the index.
