Protein aggregation is usually mediated by denaturation and hydrophobic interaction under the presence of water molecule.In general, hydrophilic residues of proteins are exposed outside to maximize the interaction with water, and hydrophobic residues are buried inside to minimize the contact with water.However, when hydrophobic residues of proteins are exposed outside by denaturation, amyloid fibrillation is initiated by hydrophobic interaction of the exposed residue.Although both denaturation and hydrophobic interaction have been regarded as a driving force of amyloid fibrillation, it is not yet clear what conditions are related to two factors.