Studies of phosphorus metabolism by isolated nuclei. XII. Some fundamental properties of the incorporation of ³²Pi into polyphosphate by rat liver nuclei

Rat liver nuclei incubated in vitro catalyze a sustained incorporation of³²Pi into polyphosphate. A preliminary estimate indicates a minimal rate of 10 moles of Pi incorporation into polyphosphates/h/mg protein. Polyphosphate is the predominant acid-insoluble product of nuclear phosphorylation; its formation is dependent on the presence of a divalent cation and is catalyzed by a system or systems as yet uncharacterized.