Inhibition of polyphenol oxidase obtained from various sources by 2,3‐diaminopropionic acid

This paper reports for the first time the inhibition of the catecholase activities of mushroom, artichoke (Cynara scolymus L) and Ocimum basilicum L polyphenol oxidase by 2,3‐diaminopropionic acid. Polyphenol oxidases from artichoke and O basilicum L were purified by ammonium sulfate precipitation, dialysis and a Sepharose 4B‐L ‐tyrosine‐p‐aminobenzoic acid‐affinity column. In inhibition studies, 2,3‐diaminopropionic acid showed uncompetitive inhibition for mushroom PPO using catechol and pyrogallol as substrates, competitive inhibition for O basilicum L PPO using catechol as a substrate, and uncompetitive inhibition for artichoke PPO using catechol as a substrate. Furthermore, sodium azide, which is an inhibitor of PPO, was used as an inhibitor for comparison with the inhibition potency of 2,3‐diaminopropionic acid. The highest 2,3‐diaminopropionic acid inhibition observed with O basilicum L (K_i = 0.89 mM ), followed by artichoke (K_i = 1.42 mM ) and mushroom (K_i = 2.47 mM ), respectively. Copyright © 2005 Society of Chemical Industry