Abstract:

When the trypsin interacts with herring sperm DNA(hsDNA),salmen sperm DNA(sDNA) and calf thymus DNA(ctDNA) to form the binding products,the Resonance Rayleigh scattering(RRS) are obvious enhanced remarkably and new RRS spectra appear. They have similar characteristics of RRS spectra,the maximum RRS peaks are at 307 nm(hsDNA,sDNA) and 290 nm(ctDNA),and the other peaks are  at 350 nm. As the scattering intensity is proportion to the concentration of DNA or trypsin respectively,the reaction can also be used as a new method for the determination of trypsin with DNA and for the determination of DNA with trypsin. When it  is used  for the determination of  DNA with trypsin,the linear range are 1.4×10^-3—2.3 μg/mL(hsDNA),2.1×10^-3—2.5  μg/mL(sDNA) and 3.5×10^-3—1.9 μg/mL(ctDNA),and the detection limits are 0.4 μg/mL(hsDNA),0.7  μg/mL(sDNA) and 1.1 μg/mL(ctDNA),respectively. When it is used for the  determination of trypsin with hsDNA,the linear range is between 0.1 ng/mL and 30.0 μg/mL,and its detection limit is 39.0 ng/mL. In this  paper,the optimal interaction conditions,the affecting factors,the properties of analytical chemistry of the binding complex and the binding ratio of trypsin with DNA were investigated. The binding mode,binding ratio of trypsin with DNA and the reasons for the enhancement of RRS intensity are also discussed. A highly sensitive,simple and quick method for the determination of trace amount of DNA with trypsin as a RRS probe was developed.

Key words: Trypsin;   hsDNA;  sDNA;  ctDNA;  Resonance Rayleigh scattering