[9] Generation of the 40 or 42 amino acid-long amyloid-β peptides that aggregate in the brain of Alzheimer's patients requires two sequential cleavages of the amyloid precursor protein (APP).

Unlike APP and the presenilin proteins important in γ-secretase, no known mutations in the gene encoding BACE1 cause early-onset, familial Alzheimer's disease, which is a rare form of the disorder.

The physiological purpose of BACE's cleavage of APP and other transmembrane proteins is unknown: some studies observed that BACE1 is involved in myelination (it is co-express with neuregulin 1 type III).

[11][12] Drugs to block this enzyme (BACE inhibitors) in theory would prevent the buildup of beta-amyloid and (per the Amyloid hypothesis) may help slow or stop Alzheimer's disease.

[18] In February 2017, Merck halted its late-stage trial of verubecestat for mild to moderate Alzheimer's disease after it was reported as having "virtually no chance" of working according to an independent panel of experts.

Recently, Lilly reported that the phase II trial of LY2886721 was terminated due to liver abnormalities that were found in 4 out of 45 patients (Rogers, 2013).

[22] These results raise the possibility that BACE inhibiting drugs currently being investigated for the treatment of Alzheimer's may have significant side effects related to impaired motor coordination,[23] though BACE1 knockout mice are healthy.