Effect of Sodium Dodecyl Sulphate on Partial Purified Polyphenol Oxidase Activity in Red and Green Tomatoes (Solanum Lycopersicum)

In order to better understand how to prevent enzymatic greenning, it is important to understand  kinetic properties of polyphenol oxidase.  we investigated the effect of SDS on the rate of catechol oxidation by small cherry tomato partial purified PPO. PPO activity increased with increasing SDS concentration. The most effective concentration of SDS was 0.8, 1 and 1.25 mM in according to pH and type of substrate, where the measured activity was 0.074 and 0.247 units/mg.protein at pH 6.7 and 0.159 and 0.118 unit/mg.protein at pH 8 for catechol and pyrogallol, respectively. The activation of field small cherry PPO increased linearly with the SDS concentration up to 1 – 1.5 mM and decreased thereafter. The activity of small cherry PPO was also enhanced 1.7-fold by exposure to SDS at pH 8.0 in presence of catechol, 1.8-fold by exposure to SDS at pH 8.0 in presence of pyrogallol, 2.3-fold by exposure to SDS at pH 6.7 in presence of catechol and 2.6-fold by exposure to SDS at pH 6.7 in presence of pyrogallol. Therefore sodium dodesyl sulphate is an activator of polyphenol oxidase that  can probably change latent form of enzyme to active form, so increases the activity of polyphenol oxidase