CHARACTERIZATION OF A NOVEL PROCESSING PATHWAY FOR ALZHEIMERS AMYLOID-BETA PRECURSOR PROTEIN

Amyloid beta (A beta) is a normal proteolytic fragment of a large prec ursor protein (beta PP) which undergoes altered conformation, leading to fibril formation. Two main PPP processing pathways have been descri bed, and we are now reporting the characterization of a third beta PP pathway. A membrane-associated 16 kDa component identified in human pl atelets isolated from normal donors. Based on size, immunoreactivity a nd amino acid sequence analysis, the fragment is a C-terminal PPP comp onent which starts at position 642 (APP(770) numbering) and contains t he intact go sequence. The presence of this novel pathway of beta PP p rocessing in resting platelets suggest that it occurs as a normal even t.