It is of great interest to prepare artificial architecture of protein in thin film, which has been the focus of bioengineerign in recent years. The self-assembled films of α-amylase on the negatively charged PET(PET-CO^-~2) is fabricated and the AFM results are described in this paper. The surface of PET-CO^-~2 was covered by high-density layer of α-amylase, whose thickness was 5～10 nm. The molecules of α-amylase aggregated in the layer which was obtained from the pH 6.0 solution, and the shape of molecules became shaper, which resulted in lagr RMS. On the lower-charged substrate (PET-CO^- ~2), the aggregating molecules could be found. With raising the charge density of substrate the shape of molecules became sharper.

Key words: AMYLASE, MONOMOLECULAR FILMS, PET, POLYETHYLENE TEREPHTHALATE