. Author manuscript; available in PMC: 2010 Mar 1.

Published in final edited form as: Protein Expr Purif. 2008 Oct 19;64(1):82–88. doi: 10.1016/j.pep.2008.10.005

Table 1.

PDE8A purification

Purification Steps	Total protein (mg)	Specific activity (nmol/min/mg)	Total activity (nmol/min)	Activity recovery (%)
Refolding^*	50.0	5.6	280	100
hydroxyapatite HTP	35.0	6.0	208	74
Q-Sepharose	12.0	7.2	87	31
Sephacryl S300	7.6	11.4	87	31

Since the PDE8A catalytic domain was expressed as pellet and the cell lysate had trace activity, the pellet from 10 grams of wet cells was dissolved in 6 M guanidine and purified by Ni-NTA affinity column. A total of 50 mg purified protein from Ni-NTA was refolded and the activity from the refolding was used as the starting unit.