Figure 1: Schematic diagram of the plasmid cleavage reaction and chromatographic profile of proteins eluted from a Phenyl-Sepharose column. (a) Diagram showing various DNA products resulting from cleavage of supercoiled plasmid by the endonuclease. Various forms of pBluescript are indicated: S, supercoiled DNA; O, open-circular DNA; L, linear DNA. (b) Chromatographic profile of the protein eluted with a linear gradient of 1 to 0 M (NH4)2SO4 in 50 mM potassium phosphate buffer at a flow rate of 2 mL/min. The dashed line represents the gradient of ammonium sulfate. The inset shows the DNA cleavage activity of proteins eluted in fractions 29 to 42 determined as described in Section 2.