kinetic investigations of peroxidase in roots of gundelia tournefortii

abstract kinetic properties of root of peroxidase of gundelia tournefortii investigated at different ph, temperature and different inhibitors. maximum activity of peroxidase achieved at ph 5.5-6 in according to type of substrate. activity of peroxidase increased at constant concentration of h2o2 and different concentration of guaiacol, catechol and pyrogallol. the maximum activity in presence of 22mm of guaiacol was earned 2.4 unit/mg.protein. at constant concentration of guaiacol and different concentration of h2o2, vmax and km were 2 unit/mg.protein and 4 mm respectively. activity decreased at high concentration of h2o2 so reached to 35% of vmax at 40 mm. catalytic efficiency of peroxidase in presence of constant concentrations of guaiacol and h2o2 calculated 0.5 and 0.5 unit/mg protein mm-1 respectively. stability of enzyme and maximum of activity was earned at 40 0c. sodium cyanid and sodium azide showed inhibitory effect on activity with ic50 of 0.008 and 0.4 mm respectively. these results of inhibitors showed that inhibitory effect of azid is 312 times of inhibitory effect of cyanide. cyanid is competitive inhibitor of peroxidase in presence of catechol and pyrogallol and noncompetitive inhibitor of enzyme in presence of guaiacol, and azide is noncompetitive inhibitor of peroxidase of root in gundelia tournefortii in presence of catechol and pyrogallol and uncompetitive inhibitor of enzyme in presence of guaiacol and kojic acid is uncompetitive inhibitor of peroxidase in presence of guaiacol and pyrogallol.