TABLE 1.

Purification of the killer protein from S. occidentalis^a

Stepb	Total vol (ml)	Total protein (mg)	Total activity (107 aU)	Sp act (102 aU/mg)	Purification (fold)	Yield (%)
Culture broth	10,000	160,000	1.6	1.0	1.0	100
Ultrafiltration	880	44,000	1.1	2.5	2.5	69
QAE-Sephadex	1,000	9,200	1.0	11	11	63
Butyl-Toyopearl	2,400	31	0.6	1,900	1,900	38
Fractogel EMD COO−	44	1.5	0.2	13,000	13,000	13

^aPurification procedures are described in Materials and Methods; 1 aU, the amount of killer protein that caused a clear zone of 1 mm. 

^bQAE, quaternary aminoethyl.