 Proteases may play a role in synaptic plasticity balancing proteolytic activity and inhibition, which is controlled by proteolytic inhibitors such as alpha-2-macroglobulin.Studies have shown that a high presence of alpha-2-macroglobulin is present in the neuritic plaques in many Alzheimer patients.Isolation of cDNA encoding proteins associated with Aβ was used to discover alpha-2-macroglobulin.