The cerebral and vascular plaques associated with Alzheimer's disease are mainly composed of Amyloid beta peptides. beta Amyloid is derived from cleavage of the Amyloid precursor protein and varies in length from 39 to 43 amino acids. beta Amyloid [1-40], beta Amyloid [1-42], and beta Amyloid [1-43] peptides result from cleavage of Amyloid precursor protein after residues 40, 42, and 43, respectively. The cleavage takes place by gamma-secretase during the last Amyloid precursor protein pro

Pituitary adenylate cyclase-activating polypeptide also known as PACAP is a protein that in humans is encoded by the ADCYAP1 gene. PACAP is similar to vasoactive intestinal peptide. One of its effects is to stimulate enterochromaffin-like cells. It binds to vasoactive intestinal peptide receptor and to the PACAP receptor.