Table I.

Purification of the ExGase from the purified cell walls of developing maize seedlings

	Total Protein	Total Activity	Specific Activity	Purification
	mg	unitsa	units mg−1	-fold
Cell wall extractb	26.2	1,845	70	1
SP-Sephadex	11.2	1,163	104	1.5
S-300 HPLC	1.10	538	489	7
Con-A	0.21	305	1452	21.7
Hydroxyapatite	0.11	290	2636	37.6

^aOne unit is defined as the capacity to produce 1 μmol Glc mg⁻¹ protein min⁻¹. 

^bCell walls were purified from 1.5 kg of maize seedlings; the cell wall proteins were extracted with 3.5 m LiCl, the protein extract was concentrated to about 50 mL, and dialyzed against 20 mm sodium acetate, pH 5.0, containing 20 mm NaCl.