Amyloid beta peptide (Aβ peptide) (Aβ)

Amyloid beta peptide (Aβ) denotes a family of peptides of approximately 38–43 amino acids, most commonly Aβ40 and Aβ42, generated by sequential cleavage of the amyloid precursor protein (APP) by β-secretase and the γ-secretase complex. Aβ exists as monomers, soluble oligomers, protofibrils, and insoluble fibrils that accumulate into extracellular amyloid plaques, a pathological hallmark of Alzheimer’s disease. Structural and biophysical studies show Aβ peptides are intrinsically disordered in solution but adopt β-sheet–rich conformations upon aggregation; Aβ42 aggregates more readily and is more neurotoxic than Aβ40. Therapeutically, Aβ is a validated target for anti-amyloid antibodies that bind aggregated species to facilitate clearance, and upstream secretase modulators aim to reduce production; Aβ species and amyloid imaging serve as key biomarkers for diagnosis and treatment selection.

Other names

Amyloid-βBeta-amyloidAβ40Aβ42Amyloid beta (1–40)Amyloid beta (1–42)Aβ peptide 38–43Amyloid-β peptide

Antibody-mediated clearance of Aβ aggregates/protofibrils/fibrils via microglial engagement and peripheral sink effects Inhibition/modulation of APP processing to reduce Aβ production (β-secretase and γ-secretase pathways) Stabilization or inhibition of Aβ oligomerization/fibrillization to reduce neurotoxic species