Glucagon is a 29 amino acid containing peptide hormone processed from proglucagon. As a counterregulatory hormone for insulin, glucagon plays a critical role in maintaining glucose homeostasis in vivo in both animals and humans. Not surprisingly, glucagon and glucagon receptor have been pursued extensively as potential targets for the therapeutic treatment of diabetes. As Aβ peptides and IAPP, glucacon tends to form gel-like fibrillar aggregates. These fibrils were found to be toxic through the activation of apoptotic signaling pathways. Hence the aggregation behavior of glucagon has been studied extensively.