Purification of acetokinase from Desulfovibrio desulfuricans.

The formation of acetyl phosphate and adenosine diphosphate (ADP) from adenosine triphosphate (ATP) and acetate was first recognized by F. Lipmann (J. Biol. Chem. 155:55, 1944) in extracts of Lactobacillus delbrueckii and later by E. R. Stadtman and H. A. Barker (J. Biol. Chem. 184:769, 1950) in Clostridium kluyveri. I. C. Rose et al. (J. Biol. Chem. 211:737, 1954) purified the acetokinase of Escherichia coli and elucidated many of its properties. They showed that the enzyme was relatively specific for acetate and propionate and that inosine triphosphate (ITP) was capable of replacing ATP as the phosphorylating agent. Mg+ or Mnwas required for its activity, and an enzymatic method for the determination of acetate was introduced by these workers. Desulfovibrio desulfuricans reduces inorganic sulfate, by a dissimilatory pathway, to hydrogen sulfide. The overall process requires an initial expenditure of ATP, and one step in the regeneration of ATP is the action of acetokinase on acetyl phosphate and ADP (H. D. Peck, J. Biol. Chem. 235:2734, 1960). Because of its importance in conserving the high energy nature of acetyl phosphate, the acetokinase of D. desulfuricans was partially purified, and several of its properties were examined. D. desulfuricans, strain 8303, was grown in