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Amyloid-β 42
42
Human amyloid-β peptide Aβ1–42. Forty-two residues.
The more pathogenic human amyloid-β peptide is forty-two amino acids long. Aβ42 is named for that length. It is not the more abundant 40-residue form.
What it supports
A residue count that is also the catalogue name. Glenner and Wong isolated the cerebrovascular β protein in 1984. Kang et al. cloned the precursor in 1987. Later fibril structures (PDB 2MXU, 5KK3) are explicit 42-residue chains. γ-secretase sets the C-terminus. The 42-mer dominates plaque cores. Aβ40 versus Aβ42 is a real biochemical fork.
What it does not
Not a rounded lab constant. Not Aβ40. Not APP-695. Not the single cause of Alzheimer’s. Structure papers confirm the length. They are not the discovery.
ExactnessExact
Form42
Unitresidues
Strengthhard
When1984