Beta secretase 1 (BACE1) catalyses the cleavage of APP(18 770) within the ectodomain and liberates a soluble proteolytic fragment, termed soluble APP beta (APPs beta, APP(18 671)) (Parvathy et al. 1999, Kinoshita et al. 2003). APPs beta is subsequently cleaved by the presenilin (PS) containing gamma secretase complex to eventually (step wise details of multiple cleavages not shown here) liberate the neurotoxic Abeta peptides 42 and 40 (APP(672 713) and APP(672 711) respectively) (Huse et al. 2002, Ehehalt et al. 2003, Anderson et al. 2005, Fukumori et al. 2006, Takami et al. 2009, Andrew et al. 2016).