The invention provides compounds having formulae comprising <?in-line-formulae description='In-line Formulae' end='lead'?>X1-Ser-Met-Arg-Glu-Arg-X2<?in-line-formulae description='In-line Formulae' end='tail'?> in which X1 and X2 are up to 30 amino acid residues and the formula represents a reverse-order sequence corresponding to amino acid residues 332 to 328 of human APP and from zero to 30 successive amino acid residues of human APP extending in each direction therefrom, The invention also provides the pentapeptide Ser-Met-Arg-Glu-Arg, corresponding to residues 332 to 328 of human amyloid precursor protein in reverse order, and the tripeptide Arg-Glu-Arg which corresponds residues 328 to 330 of human amyloid precursor protein, the tripeptide and pentapeptide being provided as pharmaceutical compositions. The invention further provides conjugates of the foregoing compounds which can cross the blood-brain barrier and pharmaceutical compositions containing such conjugates. The compounds and compositions of the invention are believed to be useful in the treatment of Alzheimer's disease and as cognitive enhancers and appropriate methods of medical treatment are disclosed.
Polypeptides related to amyloid precursor protein, pharmaceutical compositions thereof, and methods of treatment using the same