Table 1.

Purification of ɛC-DNA glycosylase from HeLa cells

Purification step	Volume, ml	Total protein, mg	Total ɛC activity, units*	Specific activity, units/mg	Yield, %	Purification fold, %
I. Whole cell extract	533	5,785	50,816	8.8
II. Ammonium sulfate precipitate	286	3,639	40,841	11.2	80.4	1.3
III. Phosphocellulose (P11)	161	444	17,124	38.6	33.7	4.4
IV. Blue Sepharose	30	63.3	5,398	85.3	10.6	9.7
V. Mono-S	7	9	2,945	327.2	5.8	37
VI. ɛC-DNA affinity (1)	4.5	0.2	1,838	9,190	3.6	1,044
VII. ɛC-DNA affinity (2)	3.5	nd†	—	—	—	—

^*One unit of ɛC-DNA glycosylase is defined as 1 fmol of the ɛC-oligomer cleaved after 10 min at 37°C. 

^†No measurable protein was recovered but there was sufficient ɛC activity to determine that G/T mismatch activity remained.