羧甲基壳聚糖-Co(Ⅱ)配合物与鲱鱼精DNA的相互作用

Interaction of carboxymethylchitosan-Co(Ⅱ)complex with herring sperm DNA

目的研究了羧甲基壳聚糖-Co(Ⅱ)配合物与鲱鱼精DNA之间的作用方式。方法采用循环伏安法和光谱法研究了羧甲基壳聚糖-Co(Ⅱ)配合物与鲱鱼精DNA之间的作用机制。结果 (1)羧甲基壳聚糖-Co(Ⅱ)的存在导致Fe(CN)63-/4-探针分子氧化还原峰电流下降,峰值电位正移,显示羧甲基壳聚糖-Co(Ⅱ)和Fe(CN)63-/4-与DNA之间存在竞争性作用。(2)随着DNA的不断加入,羧甲基壳聚糖-Co(Ⅱ)的特征吸收峰强度逐渐降低,峰位红移;同时,中性红的加入导致羧甲基壳聚糖-Co(Ⅱ)/DNA体系的特征吸收峰发生增色效应、峰位红移并伴有等吸收点出现,表明羧甲基壳聚糖-Co(Ⅱ)、DNA与中性红三者存在新的共平衡体系,中性红对羧甲基壳聚糖-Co(Ⅱ)与DNA的作用有竞争抑制作用。结论羧甲基壳聚糖-Co(Ⅱ)能够以嵌插方式与鲱鱼精DNA发生相互作用。

Objective To investigate the interaction between carboxymethylchitosan-Co （Ⅱ ） complex （CMC-Co） and herring sperm DNA. Methods The interaction between carboxymethylchitosan-Co（ Ⅱ ） complex （CMC-Co） and herring sperm DNA was studied by cyclic voltammetry and UVVis spectra. Results Firstly, the peak current of probe molecule Fe （CN）63/4 at Au/DNA electrodes obviously de- creased and the peak potential shifted positively because of the existences of CMC-Co. All showed that there was a competitive effect between CMC-Co and Fe （CN）63-/4- with herring sperm DNA. Secondly, the UV absorption peaks of CMC-Co appeared hypochromism and red-shift phenomena, with the increase of DNA concentration; with the addition of NR into DNA-CMC-Co system dropwise, the ab- sorption peaks of DNA-CMC-Co system appeared hyperchromic, red-shift phenomena and isoehromatic point, which illustrated that there was a new co-balance system within CMC-Co, NR and DNA. Thus, a competition had existed between NR and CMC-Co with DNA because of the intercalations between NR and DNA. Conclusion A binding mode intercalation was existed between CMC-Co and herring sperm DNA.