title: Poly(ADP-ribose) polymerase is a zinc metalloenzyme.
abstract: Purified poly(ADP-ribose) polymerase was inhibited by 1,10-phenanthroline at pH less than 8. This inhibition and the inhibition by other chelating agents suggested that this enzyme was a metalloprotein. Atomic absorption spectroscopy showed the presence of one atom of zinc per protein molecule. Dialysis of the enzyme against buffers containing 1,10-phenanthroline resulted in the loss of activity and the removal of zinc from the enzyme. Initial rate kinetics showed that 1,10-phenanthroline was non-competitive with NAD+ and competitive with DNA. The binding of DNA to the enzyme was unaffected by the inhibitor. These results suggest that a metal-containing site is involved as part of the interaction of DNA and poly(ADP-ribose) polymerase.
mesh_terms: D000818:Animals; D002384:Catalysis; D002417:Cattle; D004247:DNA / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008667:Metalloproteins / Q000378:metabolism; D008970:Molecular Weight; D009244:NAD+ Nucleosidase / Q000378:metabolism*; D010618:Phenanthrolines / Q000494:pharmacology; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000302:isolation & purification / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism*
chemical_list: D008667:Metalloproteins; D010618:Phenanthrolines; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D004247:DNA; D011065:Poly(ADP-ribose) Polymerases; D009244:NAD+ Nucleosidase; D015032:Zinc