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 m odel system. Honey was a noncompetitive inhibitor of PPO catalyzed oxidatio n of catechol. The Arrhenius activation energy (Ea) of thermal inactivation od mushroom PPO differed in the presence and absence of honey. The Ea valu e 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 lo wer in the presence of honey. Characterization of the inhibitor was carried out by gel electrophoresis (SDS-PAGE and NativePAGE). An inhibitory peptid e fraction was obtained after native PAGE. The molecular weight was determi ned to be 0.6 kDa by Sephadex G-15 column chromatography.