Kinetics of catalytic hydrolysis of phosphodiester and plasmid DNA by the quaternary ammonium salt of chitosan with Zn(II)

The hydroxypropyl trimethyl ammonium chloride chitosan (HTACC) was synthesized by the reaction of chitosan with glycidyl trimethylammonium chloride. The kinetics of hydrolysis of bis(p-nitrophenyl) phosphate (BNPP) catalyzed by HTACC-Zn(II) in Tris-H ⁺ buffer was studied and analyzed. In addition, the cleavage of plasmid DNA and the molecular interaction with HTACC-Zn(II) were also investigated. The results show that the catalyst has fine catalytic activity to the hydrolysis of phosphodiesters with a first-order rate constant of k _obs=6.7×10 ^-6 s ^-1, which is 6.0×10 ^-4 folds of its spontaneous hydrolysis. Furthermore, the catalyst can cleavage plasmid DNA (pUC19) from supercoiled form to nicked form and/or linear form effectively.