Cellular forms of the rat and human beta-amyloid precursor protein (BAPP).

Using synthetic peptide antisera generated against beta-amyloid precursor protein (BAPP) sequences we demonstrate that the newly synthesized BAPP appears as a 94 kDa peptide in rat brain RNA cell-free translates or polysome runoffs, while from similar human brain material we see two bands at 94 and 120 kDa. Immunoblots reveal likely post-translational modification of BAPP, and possibly an age-dependent, endogenous proteolysis of the protein in rat brain. On human brain immunoblots an unusual post-translational modification or possibly oligomerization of BAPP is seen, particularly in cortical regions.