TABLE 1

Expression and purification of G. diazotrophicus dioxygenase

Step	Vol (ml)	Protein (mg/ml)	Total protein (mg)	Activity^a (µM · min⁻¹)	Sp act (µmol · min⁻¹ · mg⁻¹)	Purification fold	Yield (%)
Crude extract^b	6.0	15.9	95.4	1.578	0.595	1.0	100
Ni²⁺ chromatography	7.0	4.5	31.8	0.823	1.087	1.8	61

↵a Activity was determined using a 50-µl protein solution under the assay conditions.
↵b Crude extract was obtained from a cellular paste harvested from a 0.5-liter culture.