Regarding the comment about SDS-PAGE potentially inducing artifactual dimers from the natural Aβ species present in AD brain extracts (as opposed to synthetic Aβ peptides): In previous work (Shankar et al., 2008, and Jin et al., 2011), we used just non-denaturing size-exclusion chromatography to obtain fractions of 8 kDa from typical AD brain soluble extracts (made in physiological buffer [TBS]) that contained dimers which we subsequently visualized on SDS-PAGE/Western blots. These data indicate that Aβ dimers of 8 kDa existed in the cortical extracts without any denaturing steps and could then be seen as just dimers (no monomers) on the subsequent blots (see Jin et al., 2011, Fig. 1A). So, even if SDS could induce some artifactual dimers, I definitely don't think all dimers recovered from AD brain soluble extracts are formed artifactually.

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