Beta secretase enzyme interacting with a membrane, molecular model. The enzyme (white ribbons) with an inhibitor molecule (coloured, see C015/1977) is above the membrane (yellow and grey, across bottom). This enzyme, of the type known as aspartic-acid protease, 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.