A kinetic aggregation assay allowing selective and sensitive amyloid-β quantification in cells and tissues

Biochemistry. 2011 Mar 15;50(10):1607-17. doi: 10.1021/bi1013744. Epub 2011 Jan 26.


The process of amyloid-β (Aβ) fibril formation is genetically and pathologically linked to Alzheimer's disease (AD). Thus, a selective and sensitive method for quantifying Aβ fibrils in complex biological samples allows a variety of hypotheses to be tested. Herein, we report the basis for a quantitative in vitro kinetic aggregation assay that detects seeding-competent Aβ aggregates in mammalian cell culture media, in Caenorhabditis elegans lysate, and in mouse brain homogenate. Sonicated, proteinase K-treated Aβ fibril-containing tissue homogenates or cell culture media were added to an initially monomeric Aβ(1-40) reporter peptide to seed an in vitro nucleated aggregation reaction. The reduction in the half-time (t(50)) of the amyloid growth phase is proportional to the quantity of seeding-competent Aβ aggregates present in the biological sample. An ion-exchange resin amyloid isolation strategy from complex biological samples is demonstrated as an alternative for improving the sensitivity and linearity of the kinetic aggregation assay.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyloid / analysis*
  • Amyloid / metabolism
  • Amyloid beta-Peptides / analysis
  • Animals
  • Brain Chemistry
  • Caenorhabditis elegans / chemistry*
  • Endopeptidase K / metabolism
  • Kinetics
  • Mice
  • Peptide Fragments / analysis


  • Amyloid
  • Amyloid beta-Peptides
  • Peptide Fragments
  • amyloid beta-protein (1-40)
  • amyloid beta-protein (1-42)
  • Endopeptidase K