A peptide is provided which has a binding inhibitory function that inhibits binding between amylospheroids (ASPD) and neurons. The polypeptide, represented by expression (I) or (II), is synthesized, isolated or purified. X1X2X3X4 (I) In formula (I), X1 is R, H or K, X2 is R, K, D, H, W, Q, Y or T, X3 is any amino acid, and X4 is W, F or Y. X1X2X3X4 (II) In formula (II), X1 is R, H or K, X2 is any amino acid, X3 is L, G, I, W, R, M, D, E, A, V or K, and X4 is W, F or Y.本發明提供一種具有對澱粉球蛋白(ASPD)與神經細胞之結合之結合阻礙能力之肽。 於一態樣中,本發明係下述式(I)或(II)所表示之經合成、單離或精製而成之多肽。 X1X2X3X4(I) 於式(I)中, X1為R、H或K, X2為R、K、D、H、W、Q、Y或T, X3為任意之胺基酸, X4為W、F或Y。 X1X2X3X4(II) 於式(II)中, X1為R、H或K, X2為任意之胺基酸, X3為L、G、I、W、R、M、D、E、A、V或K, X4為W、F或Y。無
