This peptide is beta-amyloid (1-40) N-terminally truncated. It is the non-pyroglatamate form of beta-Amyloid (3-40). N-terminally truncated pyroglutamate-modified beta-Amyloid forms such as Aß(3-40) and Aß (11- 40) have been described as major compounds in the senile plaques. Pyro-Glu modified beta-Amyloid forms are more resistant to degradation, show higher toxicity and have increased aggregation propensity compared to non-modified beta-Amyloid.
Pyroglutamyl (pGlu) peptides may spontaneously form when either Glutamine (Q) or Glutamic acid (E) is located at the sequence N-terminus. The conversion of Q or E to pGlu is a natural occurrence and in general it is believed that the hydrophobic γ-lactam ring of pGlu may play a role in peptide stability against gastrointestinal proteases. Pyroglutamyl peptides are therefore considered a normal subset of such peptides and are included as part of the peptide purity during HPLC analysis.