Douglass: It's OK oxytetracycline tablets bp 250mg The process starts with a long protein, called APP, which is ­located across the neuron’s membrane. For reasons not yet fully understood, APP protein can be cut in several different places, producing amyloid peptides of varying lengths. Only the longer forms of the amyloid peptide carry the risk of aggregating into plaques, and people with Alzheimer’s produce an ­abnormally high number.