Pyroglutamate-3 amyloid-beta peptide (pGlu-3 Aβ) (pGlu-3 Aβ)

Pyroglutamate-3 amyloid-beta (pGlu-3 Aβ) is a highly pathogenic, N-terminally truncated, and modified form of the amyloid-beta peptide found in the brains of patients with Alzheimer's disease [PMID: 22084105]. It is formed through the cyclization of the N-terminal glutamate residue at position 3 into pyroglutamate, a reaction catalyzed by the enzyme glutaminyl cyclase [PMID: 15502824]. This modification increases the peptide's hydrophobicity, makes it resistant to proteolytic degradation, and significantly accelerates its aggregation into neurotoxic oligomers and plaques [PMID: 21531333]. Because pGlu-3 Aβ is absent in healthy brains and serves as a seed for plaque formation, it has become a primary target for immunotherapy [PMID: 27551071]. Drugs like donanemab are designed to recognize this specific epitope, enabling the selective removal of established amyloid plaques while potentially sparing non-pathogenic amyloid monomers [Eli Lilly, 2023]. Targeting this molecule aims to slow cognitive decline by reducing the overall amyloid burden and associated neurodegeneration [PMID: 34161707].

Other names

AβpE3N3pE-amyloid betaPyroglutamated amyloid-betaAβ3(pE)-42Aβ3(pE)-40

Monoclonal antibodies bind specifically to the N-terminal pyroglutamate epitope of the modified amyloid-beta peptide to facilitate its clearance from the brain via microglial phagocytosis [PMID: 34161707]. Alternatively, small molecule inhibitors target glutaminyl cyclase to prevent the formation of the pyroglutamate modification [PMID: 15502824].