Isolation, chemical characterization, and quantitation of A beta 3-pyroglutamyl peptide from neuritic plaques and vascular amyloid deposits

Biochem Biophys Res Commun. 1997 Aug 8;237(1):188-91. doi: 10.1006/bbrc.1997.7083.


From the neuritic plaques and vascular walls of the brains of patients with Alzheimer disease, we have purified and quantified an A beta peptide which starts at residue 3Glu in the form of pyroglutamyl (A beta3pE). The N-terminally truncated A beta3pE comprised 51% of the A beta in the neuritic plaques. This was followed by 30% starting at position 1Asp which included 20% in the isomerized form (IsoAsp). In contrast, the vascular amyloid only contained an average of 11% in the form of A beta3pE with the major component starting at residue 1Asp (69%), which included only 6% in the form of IsoAsp. The presence of A beta3pE has important structural consequences since it is more hydrophobic than other forms of A beta, thus increasing the insolubility of A beta. In addition, A beta3pE, with its blocked N-terminus to the action of common aminopeptidases, may result in the profuse accumulation of A beta in the neuritic plaques of Alzheimer disease.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alzheimer Disease / pathology*
  • Amino Acid Sequence
  • Aminopeptidases
  • Amyloid / chemistry
  • Amyloid beta-Peptides / chemistry*
  • Blood Vessels / chemistry
  • Brain / pathology*
  • Brain Chemistry*
  • Chromatography, High Pressure Liquid
  • Humans
  • Mass Spectrometry
  • Neurites / pathology*
  • Peptide Fragments / chemistry
  • Peptide Fragments / isolation & purification
  • Trypsin


  • Amyloid
  • Amyloid beta-Peptides
  • Peptide Fragments
  • Aminopeptidases
  • Trypsin