Fmoc-Ala-Glu-Asn-Lys-NH2 is a peptide inhibitor that selectively targets asparagine endopeptidase (AEP) and inhibits the cleavage of amyloid precursor protein (APP). AEP, a pH-controlled cysteine proteinase, plays a crucial role in the proteolytic processing of APP, and its activity is enhanced during the aging process [1].