β-Amyloid (1-42), (1-40), (1-46) and Fragments

Introduction

The molecular weight of amyloid β-protein (Aβ) is about 4kDa, which is hydrolyzed by β-amyloid precursor protein (APP) and secreted by cells. It has very strong neurotoxic effect after sedimentation in cell matrix. Amyloid-β (Aβ) is a polypeptide containing 39 to 43 amino acids produced by proteolysis of amyloid precursor protein (APP) by β- and γ-secretase. It can be produced by a variety of cells, circulating in the blood, cerebrospinal fluid and interstitial fluid, mostly combined with chaperone protein molecules, a few in a free state. The most common subtypes of Aβ in humans are Aβ 1~40 and Aβ 1~42. In human cerebrospinal fluid and blood, Aβ 1~40 is 10 and 1.5 times higher than Aβ 1~42 respectively. Aβ 1~42 is more toxic and more likely to aggregate, therefore forming the core of Aβ precipitation and triggering neurotoxicity.

Mechanism of action

Being the main component of senile plaques in Alzheimer’s disease (AD), β-Amyloid protein is derived from amyloid precursor protein via β-secretase-mediated pathway. The neurotoxicity of Aβ has been proven by abundant studies, which can be intensified by aggregation. There is a homeostasis of Aβ production and clearance in the physiological state. Genetic mutation and environment can interrupt this balance and lead to assembly and deposition of Aβ，in turn cause or accelerate the progress of AD, via oxidative stress, apotosis, inflammation, etc.

Application of β-Amyloid (1-42), (1-40), (1-46) and Fragments

Aggregation Amyloid β (Aβ) peptide has been linked to the neurodegenerative Alzheimer’s disease and implicated in other amyloid diseases including cerebral amyloid angiopathy. β-Amyloid (1-40) is a 40-residue peptide involved in the pathogenesis of Alzheimer’s disease (AD) and elderly Down syndrome by obtaining another copy of chromosome 21. β-Amyloid (1-42)，the predominant form of amyloid beta in the brain of Alzheimer’s disease and Down syndrome patients. Neuronal death was induced by action on the p75 neurotrophin receptor.

References

1. Riek, R., Güntert, P., D?beli, H., Wipf, B., & Wüthrich, K. (2001). NMR studies in aqueous solution fail to identify significant conformational differences between the monomeric forms of two Alzheimer peptides with widely different plaque‐competence, Aβ (1–40) ox and Aβ (1–42) ox. European journal of biochemistry, 268(22), 5930-5936.
2. Casley, C. S., Canevari, L., Land, J. M., Clark, J. B., & Sharpe, M. A. (2002). β‐Amyloid inhibits integrated mitochondrial respiration and key enzyme activities. Journal of neurochemistry, 80(1), 91-100.