Methods of preparation of recombinant forms of human beta-amyloid protein and uses of these proteins

A purified beta-amyloid protein consisting of an amino acid sequence at least 70% identical to the amino acid sequence of native beta-amyloid protein, and consists of a sequence represented by the formula [X+Y], wherein

• “X” consists of one or more amino acids located at the amino terminus of the purified protein selected from the group consisting of methionine, valine, and leucine, and
• “Y” comprises all or a portion of the amino acid sequence of beta amyloid protein, and contains a mutation selected from the group consisting of A2T, H6R, D7N, A21G, E22G, E22Q, E22K, D23N, A42T, and A42V, the numbers being relative to the N-terminus of the native beta-amyloid protein.