[Protein-bound mono (adenosine-diphosphate-ribose) levels during the cell cycle of the slime mold Physarum polycephalum].

In Physarum polycephalum two fractions of ADPR-protein conjugates could be differentiated on the basis of their susceptibility towards hydroxylamine. Quantitation during the cell cycle revealed independent synthesis of the two species, the NH2OH-resistant fraction being formed during S phase, while the NH2OH-sensitive conjugate increased sharply at the S/G2 boundary. These findings indicated that nuclear ADP-ribosylation reactions are more than one function.