Description_x000D_ Application_x000D_ Human β-secretase or BACE1 has been used to study the binding reaction between amyloid precursor protein and β-secretase. It has also been used in BACE1 assay._x000D_ Biochem/physiol Actions_x000D_ BACE1 (β−Secretase or β−Site APP-Cleaving Enzyme) is a transmembrane protease responsible for the β site cleavage of the amyloid precursor protein (APP) to produce amyloid β peptide (Aβ). The accumulation of Aβ in the brain is a primary cause for the progression of Alzheimer′s, therefore BACE1 is a target for inhibitor drug discovery._x000D_ BACE1 (β-site APP-cleaving enzyme 1) is a transmembrane aspartyl protease responsible for cleaving the amyloid precursor protein (APP). BACE1-mediated cleavage of amyloid precursor protein (APP) is the first step during the generation of pathogenic amyloid-β peptides, hence making it the major drug target for Alzheimer′s disease (AD). Increased levels of enzymatic activity of BACE1 was found in cerebrospinal fluid from patients having both mild cognitive impairment (MCI) and AD, thereby suggesting the importance of BACE1 enzymatic activity in conversion of MCI to AD._x000D_ Unit Definition_x000D_ One unit will hydrolyze 1.0 picomole of 7-methoxycoumarin-4-acetyl-[Asn670, Leu671]-Amyloid β/A4 Precursor Protein 770 Fragment 667-676-(2,4-dinitrophenyl)-Lys-Arg-Arg amide substrate per 1 minute at pH 4.5 at 37 °C._x000D_ Physical form_x000D_ Solution in 20 mM Hepes, pH 7.4, 125 mM NaCl.