Ion-exchange chromatographic purification of APP. (a) Elution profile of APP from a DE-52 cellulose column. (b) Mono Q column chromatogram of APP. Conditions are described in Section 2. The fractions associated with peaks 1, 2 and 3 exhibited activity that increased the production of NO production by LPS-stimulated RAW 264.7 macrophages. Electrophoretic analyses revealed that fractions of peaks 2 and 3 contained the same protein, APP.