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Amyloid beta: Difference between revisions
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(Created page with "== Introduction == Amyloid beta (Aβ) is a peptide of 36–43 amino acids that is crucially involved in the pathogenesis of Alzheimer's disease (AD). It is derived from the amyloid precursor protein (APP) through sequential proteolytic processing by β-secretase and γ-secretase. The aggregation of amyloid beta into plaques is a hallmark of AD, contributing to neurodegeneration and cognitive decline. == Structure and Formation == Amyloid beta is produced through the p...") |
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Amyloid beta is produced through the proteolytic cleavage of APP, a transmembrane protein. The cleavage process involves two key enzymes: β-secretase (BACE1) and γ-secretase. Initially, BACE1 cleaves APP to produce a soluble fragment and a membrane-bound fragment known as C99. Subsequently, γ-secretase cleaves C99 within the membrane, releasing amyloid beta peptides of varying lengths, predominantly Aβ40 and Aβ42. | Amyloid beta is produced through the proteolytic cleavage of APP, a transmembrane protein. The cleavage process involves two key enzymes: β-secretase (BACE1) and γ-secretase. Initially, BACE1 cleaves APP to produce a soluble fragment and a membrane-bound fragment known as C99. Subsequently, γ-secretase cleaves C99 within the membrane, releasing amyloid beta peptides of varying lengths, predominantly Aβ40 and Aβ42. | ||
[[Image:Detail-79219.jpg|thumb|center|3D structure of amyloid beta peptide.|class=only_on_mobile]] | |||
[[Image:Detail-79220.jpg|thumb|center|3D structure of amyloid beta peptide.|class=only_on_desktop]] | |||
The Aβ42 variant is more prone to aggregation than Aβ40 and is considered more pathogenic. The propensity of amyloid beta to form oligomers, protofibrils, and fibrils is a key factor in its neurotoxicity. | The Aβ42 variant is more prone to aggregation than Aβ40 and is considered more pathogenic. The propensity of amyloid beta to form oligomers, protofibrils, and fibrils is a key factor in its neurotoxicity. | ||