Investigation of Activity of Partial Purified Polyphenol Oxidase in Wild Pears (Pyrus Communis) in Presence of Sodium Dodesyl Sulphate - TI Journals

A B S T R A C T In order to better understand how to prevent enzymatic greenning, it is important to understand kinetic properties of polyphenol oxidase. vegetable markets projected for the future will not occur if enzymatic greenning is not understood and controlled. We investigated the effect of SDS on the rate of catechol oxidation by wild pears partial purified PPO. PPO activity increased with increasing SDS concentration. The most effective concentration of SDS was 0.9 and 1 mM in according to pH and type of substrate, where the measured activity was 782 and 3200 units/mg.protein at pH 5 and 380 and 1100 unit/mg.protei.n at pH 7 for catechol and pyrogallol, respectively at 1 mM SDS. The activation of pears PPO increased linearly with the SDS concentration up to 1 mM and decreased thereafter. The activity of pear PPO was also enhanced 2.6-fold by exposure to SDS at pH 5.0 in presence of catechol, 3.7-fold by exposure to SDS at pH 5.0 in presence of pyrogallol, 1.7-fold by exposure to SDS at pH 7 in presence of catechol and 1.7- fold by exposure to SDS at pH 5 in presence of pyrogallol. SDS has activating effect on polyphenol oxidase in presence of both dihydroxy and trihydroxy phenols, So that, this activating effect at pH 5 is more than activating effect at pH 7.