Culture medium from cells co-expressing ChSy-2–ProA and ChPF–His, ChSy-1–His, or EXT-1–His, co-expressing ChSy-1–ProA and ChPF–His, or co-expressing EXT-2–ProA and EXT-1–His was purified with Ni2+-NTA agarose and subjected to SDS/PAGE. Separated proteins were transferred to PVDF membrane by Western blotting, allowed to react with IgG as a primary antibody, and visualized using the ECL® advance kit. Lane 1, ChSy-2–ProA and ChSy-1–His; lane 2, ChSy-2–ProA and ChPF–His; lane 3, ChSy-1–ProA and ChPF–His; lane 4, ChSy-2–ProA and EXT-1–His; lane 5, EXT-2–ProA and EXT-1–His.