Inactivation of Polyphenoloxidase by Pulsed Light

TLDR

The study examined how pulsed light inactivates polyphenoloxidase in model solutions, varying enzyme concentration and total energy dose. Inactivation is attributed to protein structural changes, including cleavage, unfolding, and aggregation. PPO inactivation rose with light dose, achieving complete inactivation above 8.75 J cm⁻²; low concentrations (4–10 U) were highly inactivated, whereas higher concentrations reduced inactivation due to conformations less prone to rearrangement.

Abstract

Abstract The effect of pulsed light on the inactivation of polyphenoloxidase (PPO) in model solutions was investigated focusing on the effect of enzyme concentration and total energy dose of the treatment. PPO inactivation increased with the dose of the treatment. Complete enzyme inactivation was achieved by pulsed light doses higher than 8.75 J cm −2 . At low PPO concentrations (4 to 10 U), the enzyme resulted highly inactivated by pulsed light treatment. Further increase in enzyme units determined a progressive decrease in PPO inactivation. The latter was attributed to protein structural modifications including cleavage and unfolding/aggregation phenomena. PPO amounts higher than 10 U probably favoured enzyme conformations that were less prone to intermolecular rearrangements leading to inactivation.