Endogenous inhibitor of the ADP‐ribosylation of (a) G‐protein(s) as catalyzed by pertussis toxin is present in rat liver

Abstract
The inhibitor activity of the ADP‐ribosylation of (a) G‐protein(s) as catalyzed by pertussis toxin was found in the membrane extract of rat liver. The inhibitor activity was found in the fractions of DEAE‐Sephacel column chromatography at 50–120 mM NaCl. The inhibitor activity is not due to the degradation of NAD nor to the reverse reaction of pertussis toxin (removal of incorporated ADP‐ribose). The present result suggests the presence of an endogenous inhibitor of the ADP‐ribosylation reaction of (a) G‐protein(s).