The molecular basis for the inhibition of the Ca2+,Mg2+ dependent endonuclease resulting from the formation of poly (adenosine diphosphate ribose) (ADP Rib) was studied in a simplified system containing purified rat liver or bull semen endonuclease, purified rat liver poly (ADP Rib) synthetase, [3H]NAD+, and DNA. Poly (ADP Rib) synthetase activity was stimulated when Ca2+,Mg2+ dependent endonuclease was added to the reaction mixture in place of histones, suggesting that the endonuclease can act as an acceptor for ADP Rib. Evidence was presented to show that the ADP Rib moiety of [3H]NAD+ was incorporated in the endonuclease fraction. The [3H]ADP Rib bound to endonuclease was in the form of monomers and oligomers and not long chain polymers. The present results suggest that the Ca2+,Mg2+ dependent endonuclease was ADP ribosylated when the endonuclease was incubated with poly (ADP Rib) synthetase and NAD+.
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Publication status||Published - 1975|
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