Table I.

Purification of high-pI α-glucosidase from 5.7 kg of barley malt flour

Fraction	Activity with Maltose	Protein	Specific Activity	Yielde	Purification
	units	E280	U/E280	%	-fold
Extract	14,400	936,000	0.015	100	1
20%–70% Ammonium sulfate	8,300	72,530	0.11	58	8
Fractogel DEAEa	1,630	16,850	0.1	11 (58)	6
First Fractogel COO−b	1,030	660	1.6	7 (36)	103
Second Fractogel COO−c	580	155	3.8	4 (20)	250
Butyl-Sepharose	150	6	25.0	1 (5)	1,590
Third Fractogel COO−d	55	0.5	110.0	0.4 (2)	7,300

^aActivity in the pass-through and wash in 20 mm HEPES and 5 mm CaCl₂, pH 7.5. 

^bNaCl gradient elution in 50 mm sodium acetate and 5 mm CaCl₂, pH 5.5. 

^cRechromatography. 

^dNaCl gradient elution in 20 mm HEPES and 5 mm CaCl₂, pH 7.3. 

^eValues in parentheses indicate the recovery corrected for the presence of low-pI α-glucosidase in the first two steps (see text).