Harnessing over a decade's worth of experience and a multi-level technology
platform that includes peptides, antibodies, dyes and assay kits, AnaSpec, EGT
Group is one of the world's most trusted sources of integrated proteomic solutions
specifically designed for Alzheimer's Disease research.
Our large collection of ß-Amyloid (1-42) peptides includes:
Native sequences – human and mouse/rat
sequences (unless otherwise specified, sequences are human in origin)
Single or multiple amino acid substitution
sequences, e.g. S26C
Biotin labeled sequences – N or C
terminally labeled, with or without linker
Dye labeled sequences – HiLyte Fluor™
or classic dye labeled
ClearPoint™ heavy-isotope labeled sequences
Shorter sequences that end on the 42nd
amino acid and analog
HFIP treated β-Amyloid (1-42)
ß-Amyloid (Aß) peptides are generated as cleavage products 39
to 43 amino acids in length from the membrane protein, Amyloid Precursor Protein
(APP) by two proteases, β-secretase and γ-secretase.1-3 While only
a small amount is processed by β-Secretase, also known as BACE1 (β-secretase
APP cleaving enzyme) or memapsin, APP is predominantly processed by α-Secretase,
producing a 83-amino acid C-terminal fragment, C83. Subsequent cleavage of C83
by γ-secretase produces a non-toxic N-terminal 3kD protein.1-2
Aßs are amphiphilic peptides with a hydrophilic N-terminal domain (residues
1 to 28) and a hydrophobic C-terminal (residues 29 to 40-42), the latter corresponding
to a part of the transmembrane domain of APP.4 β-Amyloid assembly
into fibrils is initiated by a conformational transition from random coil to
β-sheet (hence the name β-amyloid) and a nucleation-dependent aggregation process.4
Aβ peptides that are 39 to 42 amino acid residues in length with
a molecular mass of approximately 4 kDa are the core components of neuritic
plaques seen in Alzheimer’s disease (AD) brains. The presence of excess amount
of Aß deposits and neurofibrillary tangles, NFTs, 5-6 comprising
of hyperphosphorylated Tau proteins are the hallmarks of an AD brain.1
Aβ (1-42), a major component of amyloid plaques, accumulates in neurons
of Alzheimer’s disease (AD) brains. Biochemical analysis of the amyloid peptides
isolated from AD brain indicates that Aβ (1-42) is the principal species
associated with senile plaque amyloids, while Aβ (1-40) is more abundant
in cerebrovascular amyloid deposit.7-8
Figure 1. A schematic diagram of the amyloid precursor protein
(APP) and the cleavage sites of α, β and γ-secretases (diagram modified from
Wikipedia: The free encyclopedia. (2008, Mar 12). FL: Wikimedia Foundation,
Inc. Retrieved March 12, 2008, from http://en.wikipedia.org/wiki/Image:APP_cleavage.png).
Figure 2. Comparison of the human and mouse/rat b-amyloid
Table 1. A listing of ß-amyloid (1-42) and related peptides. Shaded row
denotes that the peptide sequence is of mouse/rat origin (unless otherwise
specified, all Aß peptides are of human origin).
Figure 3. Emission spectra of four of the fluorescent dye-labeled β-amyloid
2. Examples of dye-labeled β-amyloid (1-42) peptides.
Beta-Amyloid (1-42), FAM-labeled
Beta-Amyloid (1-42), HiLyte Fluor™ 488-labeled
HiLyte Fluor™ 488-DAEFRHDSGYEVHHQKLVFFAEDVGSNKGAIIGLMVGGVVIA
Beta-Amyloid (1-42), HiLyte Fluor™ 555-labeled
HiLyte Fluor™ 555-DAEFRHDSGYEVHHQKLVFFAEDVGSNKGAIIGLMVGGVVIA
Beta-Amyloid (1-42), TAMRA-labeled
1. Selkoe DJ. Nature 399, A23 (1999).
2. Suh, Y-H. and F. Checler, Pharmacol Rev 54, 469 (2002).
3. Kang, J. et al. Nature 325, 733 (1987).
4. Jarrett, JT. et al. Biochem 32, 4693 (1993).
5. Masters, CL. et al. EMBO J 4, 2757 (1985).
6. Braak, H. et al. Acta Neuropathol 87, 554 (1994).
7. Nagele, R. et al. Neurosci 110, 199 (2002).
8. Garzon-Rodriguez, W. et al. J Biol Chem 272, 21037 (1997).