TABLE 2.

Recovery of Ki-4(scFv)-ETA′ from E. coli BL21(DE3) cultured under osmotic-stress conditions in the presence of 10 mM glycine betaine

Step	Purification dataa			Relative biological activity (RU/mg)b under the indicated conditions
	Total vol (ml)	Protein concn (mg/ml)c	Total protein (mg)	Osmotic stress + compatible solutes	Standard conditions
Periplasmic extract	50	12 (±0.85)	600 (±42.5)	0.006	0.001
IMAC eluate	2	2.85 (±0.13)	5.7 (±0.26)	0.6	Not detectable
SECd eluate	3	0.37 (±0.06)	1.11 (±0.18)	3.6	Not detectable

^aRecoveries are based on 4.1 g of E. coli (wet weight) obtained from 1 liter of shaking culture. After IMAC, the 250 mM imidazole fractions were pooled, and after SEC, the fractions with the highest binding activity were pooled. 

^bCalculated by measuring the extinction at 405 nm (determined by ELISA) per milligram of protein in the pooled fractions. 

^cMean concentrations from five different experiments. 

^dSEC, size exclusion chromatography.