Biocatalysis by metallated cyclotriphosphazenes: L2Zn(NO3)2 {L = spiro-N3P3[O2C12H8][N(CH3)NH2]} as a synthetic phosphoesterase and nuclease

Abstract

Catalytic activity of [L2.Zn][NO3]2] (L = spiro-N3P3[O2C12H8][N(CH3)NH2]) towards the hydrolysis of two phosphodiesters, [bis(p-nitrophenyl)phosphate, bNPP] and [2-(hydroxypropyl)-p-nitrophenyl phosphate, hNPP] has been examined. While the rate of hydrolysis of the former is accelerated over a million-fold, the rate of hydrolysis of the latter also is enhanced considerably. Detailed kinetic evaluation of these reactions has been carried out and all the kinetic parameters including the Michaelis-Menten parameters are reported. The catalyst [L2.Zn][NO3]2] has also been found to be an effective nuclease. Relaxation of supercoiled plasmid DNA, pBR322, occurs in presence of [L2.Zn][NO3]2 without the need for any exogenous reagents.