Amyloid beta

Amyloid beta peptide (beta-APP)
A partially folded structure of amyloid beta(1 40) in an aqueous environment (pdb 2lfm)[1]
Identifiers
Symbol	APP
Pfam	PF03494
InterPro	IPR013803
SCOP2	2lfm / SCOPe / SUPFAM
TCDB	1.C.50
OPM superfamily	304
OPM protein	2y3k
Membranome	45
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

amyloid beta (A4) precursor protein (peptidase nexin-II, Alzheimer disease)
Processing of the amyloid precursor protein
Identifiers
Symbol	APP
Alt. symbols	AD1
NCBI gene	351
HGNC	620
OMIM	104760
RefSeq	NM_000484
UniProt	P05067
Other data
Locus	Chr. 21 q21.2
Search for Structures Swiss-model Domains InterPro

Amyloid beta (Aβ or Abeta) denotes peptides of 36–43 amino acids that are the main component of the amyloid plaques found in the brains of people with Alzheimer's disease.^[2] The peptides derive from the amyloid-beta precursor protein (APP), which is cleaved by beta secretase and gamma secretase to yield Aβ in a cholesterol-dependent process and substrate presentation.^[3] Aβ molecules can aggregate to form flexible soluble oligomers which may exist in several forms. It is now believed that certain misfolded oligomers (known as "seeds") can induce other Aβ molecules to also take the misfolded oligomeric form, leading to a chain reaction akin to a prion infection. The oligomers are toxic to nerve cells.^[4] The other protein implicated in Alzheimer's disease, tau protein, also forms such prion-like misfolded oligomers, and there is some evidence that misfolded Aβ can induce tau to misfold.^[5][6]

A study has suggested that APP and its amyloid potential is of ancient origins, dating as far back as early deuterostomes.^[7]