The hydrolytic kinetics of p-nitrophenol acetate (NA) catalysized by zinc(II) complex of 6-(2'-hydroxyl-3', 5'-dibromo)-benzyl-1, 4, 8, 11-tetraazacyclotetradecane has been studied. It was shown that the catalytic hydrolytic rate was of first-order to both zinc(II) complex and NA concentrations. The second-order rate constant kcat=0.12 mol^-^1. L. s^-^1 (298K, I=0.10, 0.02 mol.L^-^1 tris buffer). This is one of the most efficient hydrolytic metalloenzyme model compounds reported up to now. The present results show that coordinated phenolate can serve as a new nucleophile that effectively catalyzes the hydrolysis of NA.

Key words: ZINC COMPLEX, SIMULATION, PHENOL, NITROGEN HETEROCYCLICS, REACTION RATE CONSTANT, HYDROLASE, CATALYTIC REACTION