APOE and Alzheimer disease: Mercury would then accumulate in the tissuesof APOE-ε4 individuals, whichwould aggravate the toxic effects, which possibly could include Hg-inducedneurodegeneration and AD.6 To the bestof our knowledge, no one has so far tested this hypothesis experimentally.Here, we use the biophysical techniques circular dichroism (CD) andfluorescence spectroscopy to study in vitro the bindinginteractions between inorganic Hg(I) and Hg(II) ions and the threedifferent ApoE protein variants.