Table 1.

Purification of recombinant NirK from N. oceani NS58

Purification step	Volume	Total protein	Total activity	Specific activity	Yield
	(mL)	(mg)	(mmol of NO2− min−1)	(μmol of NO2− min−1 mg−1)	(%)
Insoluble fraction	20.0	426	n.d.	n.d.	—
Soluble fraction	40.0	346	n.d.	n.d.	—
Dialyzation	80.0	203	5.93	29.2	100
Anion exchange	21.0	24.4	2.93	120	49.3
Gel-filtration	21.0	8.79	2.95	336	49.8
Hydrophobic	8.0	1.23	2.67	2,181	45.1

n.d., not determined.