BACE1 and Alzheimer disease: Although there are numerous reports of impaired electron transfer in mitochondria, for example via diminished activity in complexes I to V in AD subjects (Parker et al., 1994; Maurer et al., 2000; Kim et al., 2001; Bosetti et al., 2002), and diminished complex III and IV activity in a transgenic AD mouse model (Mucke et al., 2000) we found no effect of raised BACE1 activity on mitochondrial electron transfer function in SH-SY5Y cells.