探针体耐尔蓝(NB)与DNA结合反应研究

应用微相吸附-光谱修正(MPASC)新技术研究DNA与耐尔蓝(NB)探针分子间的相互作用,分析生物大分子内静电场的形成与Langmuir吸附的关联性,测定了结合产物结合比、平衡常数等.通过在pH=10.38介质中对DNA-NB反应的光谱分析,结果表明产物结合比NB∶ DNA-P=3∶ 1、平衡常数K=3.33×105,摩尔吸收系数ε660 nm=4.81×103 L/mol cm.样品分析表明DNA回收率95.6%～108%,相对标准偏差RSD=2.8%.

Langmuir Aggregation of Nile Blue (NB) on DNA and Application

The study on the interaction of a stain with nucleic acids makes to understand the function of the genetic macromolecules and analyze the transmission of the genetic information. The combination of both the Langmuir adsorptionand the spectral correction techniquewill provide a very helpful experimental strategy for study of chromophore or its metallic complex’s adsorption in surfactant solution. This method is named Micro Phase Adsorption- Spectral Correction (MPASC) was described. It provides a very helpful experimental strategy for study of aggregation of a stain on biomacromolecules. Commonly, nucleic acid molecule contains complex spatial structure. The helix, winding and folds lead of manyholes, gulliesand grooves.Many polar bonds are nearto each other to form many microelectrostatic fields. They will selectively attract charged organic compounds in only monolayer till kinetic equilibrium. So the property constants of the aggregate may be determined such as equilibrium constant, binding ratio, etc. The adsorption of NB on DNA has been investigated at pH=10.38 and it obeyedthe langmuir monolayer adsorption. Results show that the adsorption ratio of NB to DNA(-P) is 3∶1, adsorption constant 3.33×105and real absorptivity 4.81×103L/molcm at 660 nm. By varying the operation condition, we observed that the adsorption ratio of NB to DNA decreased with increase of ionic strength and temperature and addition of ionic surfactant e.g. CTAB and SDBS. This indicates the interaction is an adsorption reaction not a complexation. This interaction has been applied to the quantitative determination of DNA in samples. In the presence of EDTA, many ions or compounds such as C2O42-, protein, acetone, alkali earths, Mn(II), Cu(II), Fe(II), Zn(II), Pb(II), Ni(II), Co(II), Cd(II) and Hg(II) did not interfered the direct determination of DNA. For analysis of samples, the recovery of DNA is between 95.6% and 108% and relative standard deviation 2.8%.