Rapid aggregation and assembly in aqueous solution of A beta (25-35) peptide

J Biosci. 2009 Jun;34(2):293-303. doi: 10.1007/s12038-009-0033-3.


The highly toxic A beta (25-35) is a peculiar peptide that differs from all the other commonly studied beta-amyloid peptides because of its extremely rapid aggregation properties and enhanced neurotoxicity. We investigated A beta (25-35) aggregation in H2O at pH 3.0 and at pH 7.4 by means of in-solution analyses. Adopting UV spectroscopy, Congo red spectrophotometry and thioflavin T fluorimetry, we were able to quantify, in water, the very fast assembling time necessary for A beta (25-35) to form stable insoluble aggregates and their ability to seed or not seed fibril growth. Our quantitative results, which confirm a very rapid assembly leading to stable insoluble aggregates of A beta (25-35) only when incubated at pH 7.4, might be helpful for designing novel aggregation inhibitors and to shed light on the in vivo environment in which fibril formation takes place.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyloid beta-Peptides / chemistry*
  • Benzothiazoles
  • Congo Red / pharmacology
  • Humans
  • Hydrogen-Ion Concentration
  • Kinetics
  • Models, Statistical
  • Nephelometry and Turbidimetry / methods
  • Neurotoxins / chemistry
  • Peptide Fragments / chemistry*
  • Peptides / chemistry
  • Spectrometry, Fluorescence / methods
  • Spectrophotometry, Ultraviolet / methods
  • Thiazoles / chemistry
  • Time Factors
  • Water / chemistry


  • Amyloid beta-Peptides
  • Benzothiazoles
  • Neurotoxins
  • Peptide Fragments
  • Peptides
  • Thiazoles
  • amyloid beta-protein (25-35)
  • Water
  • thioflavin T
  • Congo Red