Partial purification and characterization of the cation-binding protein and megamodulin from E. coli

Megamodulin was partially purified from E. coli by the steps of Bio-Gel P-6DG and Sephadex G-100 filtrations, and DEAE-cellulose ion-exchange. It is a heat-stable, trypsin-labile, and acidic protein which appears to be a large molecule in aggregated 'holo' form. In addition, its dissociation into smaller fragments, cation-binding capacity, interaction with basic proteins, and stimulation of megamodulin-dependent protein kinases (M-PK) from rabbit brain or skeletal muscle, were also demonstrated.