In case of AD, Aβ is generated in the amyloidogenic pathway, a multi-step cleavage process of the amyloid precursor protein (APP) [12,13] and pyroglutamate Aβ (pE3-Aβ) is formed enzymatically during posttranslational peptide maturation via cyclization of N-terminal glutamate residues of truncated Aβ(3-×) species by QC-like enzymatic activity [2,14]. The gene discussed is APP; the disease is Alzheimer disease.