Chlorogenic acid (CQA) is one of the major polyphenols in apple and a good substrate for the polyphenol oxidase (PPO) in apple. Apple contains catechins as well as CQA, and the role of CQA quinone and its interaction with catechins in the enzymatic browning of apple were examined. Browning was repressed and 2-cysteinyl-CQA was formed when cysteine was added to apple juice. CQA quinone was essential for browning to occur. Although catechins and CQA were oxidized by PPO, some catechins seemed to be non-enzymatically oxidized by CQA quinone.

Background: We explored catalytic antibodies applicable to patients.Results: A human light chain (22F6) possessing both amidase and nuclease activities and preventing infection of influenza virus was obtained.Conclusion: The 22F6 light chain holds a huge potential as a new drug for patient therapies in the future.Significance: The procedure developed in this study is highly noteworthy for developing new drugs.