Beta secretase enzyme. Molecular model of the enzyme beta secretase bound to an inhibitor molecule. Beta secretase is a membrane-associated aspartic protease, and is also known as beta-site amyloid precursor protein cleaving enzyme 1 (BACE-1). It is a transmembrane protein that is thought to play a role in Alzheimer's disease through the build up of amyloid plaques in the brain. Drugs that inhibit this enzyme may help slow the progress of the disease.