We are aware of this work. We take it very seriously, and have been re-examining APP in different experimental systems.
We will be publishing our own findings in due course. At this stage we cannot exclude the possibility that the apparent ferroxidase activity that we consistently observed was potentially an artifact of the method.
However, we are very confident that the biological properties of APP, in its ability to facilitate the export of iron through its interaction with ferroportin, is real, and reproducible.
A protein does not have to be a ferroxidase to export iron, and even if we wind up agreeing that APP lacks authentic ferroxidase activity, it still facilitates iron export, and that is the most important aspect of our original findings. No one has refuted that, more important, aspect of our discovery.
Mp>Whether or not APP is s ferroxidase is actually relatively unimportant to the biological argument.
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