Phosphorylation of adenosine 5'-monophosphate by a dialyzed cell-free extract from Escherichia coli

A cell-free extract of Escherichia coli, even after exhaustive dialysis, was found capable of phosphorylating adenosine 5'-monophosphate (AMP) to adenosine 5'-diphosphate (ADP) and adenosine 5'-triphosphate (ATP). Centrifugation at 100 000 g for 3h sedimented most of the capacity to phosphorylate AMP to ATP, while the supernatant retained a significant capacity to phosphorylate AMP to ADP. The pellet contained a greater amount of phosphate polymers (which were neither DNA, RNA, nor proteins) than did the supernatant. The addition of authentic inorganic polyphosphates to the supernatant restored the phosphorylating capacity of the original extracts. It is concluded that the observed phosphorylation is partly due to inorganic polyphosphate.