(Des-Glu²²)-Amyloid β-Protein (1-40)

The Osaka mutation was the first deletion-type mutation to be identified in APP and Aβ. The Aβ E22delta mutant is more resistant to degradation by two major Aβ-degrading enzymes, neprilysin and insulin-degrading enzyme. Synthetic mutant Aβ showed unusual aggregation properties with enhanced oligomerization but no fibrillization. It also inhibited hippocampal long-term potentiation more efficiently than wild-type Aβ. A transgenic mouse model containing APP with the E693delta mutation has been developed. APP(OSK)-Tg mice exhibit intraneuronal Aβ E22delta oligomers and memory impairment as early as eight months of age.