Beta amyloid

Beta Amyloid (β-amyloid or Aβ) is a peptide that is crucially involved in Alzheimer's disease as the main component of the amyloid plaques found in the brains of Alzheimer patients. The peptides derive from the Amyloid Precursor Protein (APP), which is cleaved by beta secretase and gamma secretase to yield Aβ. Aβ molecules can aggregate to form flexible soluble oligomers which may exist in several forms. It is believed that certain forms of these oligomers are toxic to cells.

Structure

Beta Amyloid is a 36-43 amino acid peptide composed of a portion of the transmembrane domain and the extracellular domain of the Amyloid Precursor Protein (APP). The peptide is approximately 4 kDa and its structure is dominated by a turn at residues 22 and 23, with the N-terminus and C-terminus of the peptide generally unstructured.

Function

The normal function of Aβ is not well understood. Most research suggests that Aβ has no significant role in the body. However, some research suggests that Aβ and its precursor, APP, may be involved in neuronal development and post-injury repair.

Role in Disease

Beta Amyloid is the main component of amyloid plaques in the brains of Alzheimer's disease patients. The accumulation of these plaques is thought to play a role in the degeneration of neurons and the subsequent symptoms of Alzheimer's disease.

See Also

• Alzheimer's disease
• Amyloid Precursor Protein
• Beta secretase
• Gamma secretase