A kinetic method for para-nitrophenol determination based on its inhibitory effect on the catalatic reaction of catalase

摘要

The inhibitory effect of para-nitrophenol on the catalytic reaction of catalase was investigated.Michaelis-Menten kinetic parameters were determined from Lineweaver-Burk plots obtained in the absence or in the presence of the inhibitor.The inhibitor pattern,revealed by the Lineweaver-Burk plots,suggested a fully mixed inhibition mechanism.Spectrophotometric monitoring of the indicator reaction:H2O2→(catalyst para-nitrophenol)H2O+1/2O2 in conjunction with initial rate measurements was employed for the kinetic determination of the inhibitor. Calibration plots of initial rate vs.para-nitrophenol concentration were linear in the concentration range 0.9·10~(-5)-2.5·10~(-)5 mol/L and the detection limit was 3·10~(-6) mol/L(417 mu g/L)para-nitrophenol.Interferences from other phenolic compounds like orto-cresole,meta- and orto-nitrophenol were observed.