Beta-Amyloid (1-42), Human

A? 1-42, 42-residue fragment of amyloid precursor protein, has been found to be a major constituent of the senile plaques formed in the brains of patients with Alzheimer's disease and late Down's syndrome. A? 1-42 readily forms neurotoxic oligomers at physiological pH. The sequence corresponds to the human, bovine, canine, feline, ovine, guinea pig, and rabbit A?42 peptide. The peptide has been used to detect amyloid ?-protein multimers in the cerebrospinal fluid of Alzheimer's disease patients through fluorescence correlation spectroscopy.