title: Unexpected stimulation of mitochondrial ADP-ribosylation by cyanide.
abstract: Cyanide, the classical inhibitor of the mitochondrial respiratory chain at site III, stimulates ADP-ribosylation of a number of mitochondrial proteins, the major protein being the 50-55 kDa band. Sodium azide, sharing the same inhibitory site, does not have the same effect. Rotenone or antimycin A have no influence on mitochondrial ADP-ribosylation. Data suggest that no apparent correlation exists between oxidoreductase function and protein ADP-ribosylation. Purified nuclear poly(ADP-ribose) polymerase activity was not affected by cyanide. The cyanide effect on mitochondrial ADP-ribosylation seems intriguing and may be attributed to NAD+-CN complex formation, since NAD reacts with cyanide at pH greater than 8 with N-substituted nicotinamide which may prevent inhibition of ADP-ribosylation.
mesh_terms: D000246:Adenosine Diphosphate Ribose / Q000378:metabolism*; D000818:Animals; D000968:Antimycin A / Q000494:pharmacology; D001386:Azides / Q000494:pharmacology; D003486:Cyanides / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D011190:Potassium Cyanide / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D012402:Rotenone / Q000494:pharmacology; D019810:Sodium Azide
chemical_list: D001386:Azides; D003486:Cyanides; D012402:Rotenone; D000246:Adenosine Diphosphate Ribose; D000968:Antimycin A; D019810:Sodium Azide; D011065:Poly(ADP-ribose) Polymerases; D011190:Potassium Cyanide