Effect of sodium chloride on the activity and stability of polyphenol oxidase from Fuji apple

The effect of sodium chloride on activity and stability of polyphenol oxidase (PPO, EC1.14.18.1) from Fuji apple was investigated. Partially purified PPO was activated with 0.17-3.4 M NaCl. Purified PPO stored with NaCl was stable for 2 months at 4C. PPO in the presence of NaCl (0-5.1 M) was scanned by Differential UV from 240 to 300 nm and spectral analysis showed that there were conformational changes as a function of NaCl concentration.