Inhibition of Horseradish Peroxidase Activity by Boroxine Derivative,Dipotassium-trioxohydroxytetrafluorotriborate K2[B3O3F4OH]

Recently research shows that horseradish peroxidase,hrp,when combined with other compounds,is highly reactive toward different human tumour cells and that better understanding of catalytic mechanism and inhibition hpr could lead to a new targeted cancer therapy. thus,the inhibition of hrp activity by dipotassium-trioxohydroxytetrafluorotriborate k2[b3o3f4oh] was investigated for possible explanation of previously observed antitumour activities of this promising drug. hrp activity was studied under steady-state kinetic conditions by a spectrophotometric method. in the absence of the inhibitor values of km = 0.47 mm and vmax = 0.34 mm min-1,respectively,were determined. the hydrogen peroxide h2o2 kinetic measurements show a competitive inhibition with the inhibition constant ki = 2.56 mm. the activation energy ea values were found to be very similar for both reactions; in the absence of inhibitor activation energy was 17.7 kj mol-1 and in the presence of inhibitor activation energy was 16.3 kj mol-1. the values of arrhenius constants were found to be different; a = 4.635 s-1 was measured in the absence of inhibitor while in the presence of inhibitor arrhenius constant was 1.745 s-1 showing that k2[b3o3f4oh] initiates conformational change in the structure of the hrp and subsequently reduces its activity. © 2017 jelena ostojic et al.