Debate over Alzheimer’s enzyme flares up

Controversies drive Alzheimer’s disease research. Does the buildup in the brain of a protein fragment called beta-amyloid cause the illness, or is a protein known as tau the guilty molecule?

Does a gene somewhere on chromosome 12 play a role in the brain disorder? One simmering debate concerns the identity of enzymes, dubbed gamma-secretases, that perform the final cut on amyloid precursor protein (APP) to make beta-amyloid.