TAU proteins belong to the microtubule-associated protein (MAP) family and are involved in the pathogenesis of Alzheimer’s disease. In the human brain, there are six TAU isoforms ranging from 352 to 441 amino acids in length. These isoforms vary at the carboxyl terminal according to the presence of either three repeat or four repeat domains (R1-R4), in addition to the presence or absence of one or two insert domains at the amino-terminus. Tau Peptide (45-73) is a 29-amino acid long peptide derived from the Exon 2/Insert 1 domain.