Our results indicate that Aβ peptides depositing specifically in the insoluble pools of Alzheimer’s disease brain have approximately equal amounts of BACE-1 cleaved Aβ (Asp-1 as the N-terminus) and ragged N-terminus peptide (Phe-4 residue) (Table 1, Fig. 3). The gene discussed is BACE1; the disease is early-onset autosomal dominant Alzheimer disease.