This peptide is amino acids 25 to 35 fragment of the ß-amyloid biotinylated at C-terminus. This peptide possesses many of the characteristics of the full-length ß-amyloid peptide, including an amphiphilic nature and an ability to aggregate, and can serve as a model system to study the conformational changes involved in Alzheimer's disease. Aggregates of ß-amyloid (25–35) have been shown to possess the neurotrophic and neurotoxic properties of their full-length counterparts and there is evidence that the monomeric form of the peptide may itself be cytotoxic.