Amyloid P component promotes aggregation of Alzheimer's beta-amyloid peptide.

Amyloid P component (AP) has been recognized as a beta-amyloid-associated protein but the pathological role is not known. In the present experiments, it has been shown that AP promotes the aggregation of Alzheimer's beta-amyloid peptide (A beta) in the presence of a physiological concentration of Ca2+. The aggregation promotion was observed at a concentration of soluble A beta 1-40 in human cerebrospinal fluid. The results suggest that AP is possibly a pathogenic factor of the cerebral amyloidosis.