Study on the interaction of trypsin with some DNAs and their analytical application by resonance Rayleigh scattering spectra

Abstract

When trypsin reacts with Herring sperm DNA (hsDNA), Salmon sperm DNA (sDNA), and Calf thymus DNA (ctDNA) to form a complex, the resonance Rayleigh scattering (RRS) was remarkably enhanced and new RRS spectra appear. These new spectra have similar characteristics of RRS spectra. The maximum RRS peaks are at 307 nm (hsDNA, sDNA) and 290 nm (ctDNA), and other peaks are at 350 nm. The scattering intensity is proportional to the concentration of DNA or trypsin; so this intereaction can be used to determine trypsin using DNA or DNA using trypsin. In the determination of DNA using trypsin, the linear ranges for hsDNA, sDNA, and ctDNA are 0 2.3, 0 2.5, and 0 1.9 µg " mL^-1, and the detection limits are 0.4, 0.7, and 1.1 ng " mL^-1, respectively. In the determination of trypsin using hsDNA, the linear range is 0 30.0 µg " mL^-1, and the detection limit is 39.0 ng°mL^-1. In this paper, the intereaction conditions were optimized. The affecting factors, chemical properties of the complex, and the composition ratio of trypsin with DNA were investigated. Using trypsin as RRS probe, a sensitive method for the determination of trace amounts of DNA was developed.