TABLE 2.

Purification of the cyt bc1-cy fusion complex

Step	Protein	Total activity	Specific activity	Yield	-Fold
	mg	unitsa	units/mg	%
Chromatophore + DDM	592
Solubilized chromatophore	518	2,577	4.9	100	1.0
Q-Sepharose ff	33	634	19.3	25	3.9
FLAG	8b	204	27.2	8	5.5

^aOne unit of DBH₂-dependent cyt c reduction activity was defined as the amount of enzyme that produced 1 μmol of reduced cyt c per min under the assay conditions.

^bFLAG-purified samples contained 70 and 87 nmol of cyt c (extinction coefficient, ε_551-542 of 20 mm⁻¹ cm⁻¹) and cyt b (ε_560-574 of 28 mm⁻¹ cm⁻¹) per milligram of protein, respectively.