The present invention provides a peptide capable of functioning as a mimic peptide of the amyloid beta peptide and inhibiting the fibrillation of the amyloid -. Beta. Peptide. The present invention is shown in the following formula (I): x1-as-x2-x3-x4-pro-x5-x6 (I) (x1 represents a branched amino acid, X2, X3, x4, X5 and X6 represent the same or different alpha amino acids) The amino acid sequence indicated by the amino acid sequence of 8 to 30, the following equation (III): Alternatively, the alpha amino acid may be expressed, or Z1 and Z2 may represent the same or different cysteine or serine, and when Z1 and Z2 represent cysteine, they may be cross-linked between them Peptides having an amino acid sequence of 9 to 30, including amino acid sequences indicated by the peptide, and the pharmaceutical composition containing the peptide and AMIIt relates to Lloyd \u03b2 fibrillation inhibitor.本発明は、アミロイドβペプチドのミミックペプチドとして機能し、アミロイドβペプチドの線維化を阻害しうるペプチドを提供する。本発明は、次式(I):X1-Asp-X2-X3-X4-Pro-X5-X6 (I)(式中、X1は分枝アミノ酸を表し、X2、X3、X4、X5及びX6は同一、又は異なってα-アミノ酸を表す。)で示されるアミノ酸配列を含む、アミノ酸残基数8~30のペプチド、次式(III):Z1-X13-Gly-X14-X15-Pro-Trp-Met-Z2 (III)(式中、X13、X14及びX15は同一、又は異なってα-アミノ酸を表し、Z1及びZ2は同一、又は異なってシステイン又はセリンを表し、Z1及びZ2がシステインを表す場合、これらの間で架橋されていてもよい。)で示されるアミノ酸配列を含む、アミノ酸残基数9~30のペプチド、並びに前記ペプチドを含有する医薬組成物及びアミロイドβ線維化阻害剤に関する。
