ACE and Alzheimer disease: Interactions of ACE with Aβ are important in AD (Inestrosa et al., 1996; Wang et al., 2000b; Small et al., 2007), as the peptide alters several ACE properties such as its pH optimum and inhibitor sensitivity (Geula and Mesulam, 1989), making Aβ even more neurotoxic (Inestrosa et al., 1996; Alvarez et al., 1998).