Purification of Polyphenol Oxidase from Potato and Investigation of the Inhibitory Effects of Phenolic Acids on Enzyme Activity.

Polyphenol oxidase (PPO) belongs to the oxidoreductase enzyme family.Here, PPO was purified from potato using Sepharose 4B-L-tyrosine-p-aminobenzoic acid affinity chromatography. It determined the interactions between some phenolic acids and the enzyme.The enzyme was obtained with a specific activity of 15333.33 EU/mg protein and 7.87-fold purification. It was found that phenolic acids exhibited inhibitory properties for PPO. The IC50 values of the phenolic acids were found in the range of 0.36-2.12 mM, and their Ki values were found in the range of 0.28± 0.07-1.72±0.32 mM. It was determined that studied all studied compounds displayed a competitive inhibition effect. Among these compounds, 3-hydroxybenzoic acid was found to be the most effective PPO inhibitor (Ki: 0.28±0.07 mM).Investigating the inhibition kinetics of the enzyme will simplify the testing of PPO inhibitor candidates.