High molecular weight phosphorus compound in nucleic acid extracts of the slime mold Physarum polycephalum.

Orthophosphate labeled with (32)P was added to the growth medium of the plasmodia of Physarum polycephalum. The nucleic acid extracts of such plasmodia contained (32)P that was not removed by nuclease, protease, or amylase. This labeled material was shown to be separable from nucleic acids, could be eluted from a methylated albumin-kieselguhr column at 0.5 m NaCl, was of high molecular weight, and had several characteristics in common with polyphosphate. A fraction of this polyphosphate-like material was also found in extracts of isolated nuclei.