Partial characterization of a peptide from honey that inhibits mushroom polyphenol oxidase

Mushroom polyphenol oxidase (PPO) was inhibited by one type of honey in a model system. Honey was a noncompetitive inhibitor of PPO catalyzed oxidation of catechol. The Arrhenius activation energy (Ea) of thermal inactivation od mushroom PPO differed in the presence and absence of honey. The Ea value in the presence of honey was 27.71 kJ/mol; whereas, Ea of the control was 83.14 kJ/mol. Thus, the temperature coefficient of PPO inactivation was lower in the presence of honey. Characterization of the inhibitor was carried out by gel electrophoresis (SDS-PAGE and NativePAGE). An inhibitory peptide fraction was obtained after native PAGE. The molecular weight was determined to be 0.6 kDa by Sephadex G-15 column chromatography.