blotting image indicating the presence of u03b2ctf a u03b233 it became clear that 11 types of polypeptides except 7 polypeptide among the 12 types of polypeptides mentioned above inhibit the cleavage activity of u03b2 secretase against app among these 2 4 6 1 3 5 10 8 and 9 polypeptides preferably inhibit the cleavage activity of u03b2 secretase against app more intensely with intensity increasing in this order an experiment was conducted in the same manner as experimental example 4 described above except that s4 and 4 polypeptides were used as the polypeptide and the amounts of these polypeptides added were adjusted so that the final concentrations were 1 5 10 20 50 and 100 u03bcm fig5 c shows the results in the figure u201c cont u201d indicates the negative control experiment wherein dmso was used it became clear that s4 polypeptide inhibited the cleavage activity of u03b2 secretase against app although inferior to 4 polypeptide it became clear that both s4 polypeptide and 4 polypeptide inhibited the cleavage activity of u03b2 secretase against app in a concentration dependent manner more intensively than other polypeptides an experiment was conducted wherein 1 2 and 4 polypeptides were reacted with cho k1 cells 7wd10 cells that stably expressed app protein and transiently expressed notch to confirm the production of a u03b2 protein and cleavage of notch protein to culture medium of the above cells three types of polypeptides were added in such a manner that each had a final concentration of 1 5 10 20 and 50 u03bcm thereafter sapp.