Table 1.

Purification of the RNR from P. furiosus

Step	Protein, mg	Specific activity	Total units	Purification factor
Extract	1020	0.17	173	1
Ammonium sulfate	380	0.35	133	2
Phenyl Sepharose	58	1.3	77	7.6
dATP-Sepharose	0.1	510	51	3000

One unit of activity is defined as 1 nmol of dCDP formed per min. Specific activity is given in units per mg of protein.