| SpCrossreactivity | Purified BACE/Asp2 cleaves APP and synthetic APP peptide substrates at the ¿-secretase site, and the rate of cleavage is increase 10-fold by a Swedish type mutation associated with early onset of Alzheimer?s disease. BACE has an acidic optimum (pH 4). Typically, purified BACE/Asp2 prepared by membrane solubilization in 25 mM Tris, pH 8, containing 50 mM ¿-octylglucoside retained the enzyme activity. Enzymatic reactions are performed in 50 mM 2-(N-morpholino)ethane-sulfomate, pH 5.5, containing 70 uM peptide substrate and the reaction performed at 37oC [see details in Yan et al (1999) and Lin et al (1999)]. Reaction products are then analyzed by reverse phase HPLC. |