APP and Alzheimer disease: Recently, succinylation of APP residue K612 (=K16 in Aβ) was detected in 9 out of 10 brains from AD patients, but not in age-matched controls without dementia.118 This specific residue is the cleavage site of α-secretase and involvement of this PTM in shifting APP cleavage towards amyloidogenic cleavage comes to mind.