Amyloid-beta (A beta) peptides have taken a central role in AD research, the aggregation of A beta peptide is involved in the progression of Alzheimer's disease (AD). The 35th amino acid was methionine (Met) in A beta peptides and it's redox state is critical in determining the biological activity of A beta. It has been suggested that oxidation of Met(35) (Met(35)O) plays a key role in the formation of paranuclei and in the control of oligomerization pathway choice. As an antioxidative selenoenzyme, Selenoprotein R (SelR) plays important roles in reducing the R-form of MetO to Met to maintain intracellular redox balance. However, the relationship between SelR and A beta was little investigated. Here, we found that SelR can directly interact with A beta 42, and the interaction between SelR and A beta 42 was verified by fluorescence resonance energy transfer (FRET), co-immunoprecipitation (co-IP), and pull-down assays. SelR is closely related to AD, its biological functions in human brain become a research focus. This work implies that SelR makes it capable of modulating A beta 42 aggregation and provides a novel avenue for further study on the mechanism of SelR in AD prevention. (C) 2017 Elsevier Inc. All rights reserved.