SPECIFIC-INHIBITION OF POLY(ADP-RIBOSE) GLYCOHYDROLASE BY ADENOSINE-DIPHOSPHATE (HYDROXYMETHYL)PYRROLIDINEDIOL

Adenosine diphosphate (hydroxymethyl)pyrrolidinediol (ADP-HPD), an NH analog of ADP-ribose, was chemically synthesized and shown to be a pot ent and specific inhibitor of poly(ADP-ribose) glycohydrolase. The syn thetic starting material was the protected pyrroidine, oxycarbonyl)-2- (hydroxymethyl)pyrrolidine-3,4-diol 3,4-O-isopropylidene acetal. This starting pyrrolidine was phosphorylated, coupled to adenosine 5'-monop hosphate, and deprotected, yielding the title inhibitor ADP-HPD. ADP-H DP was shown to inhibit the activity of poly(ADP-ribose) glycohydrolas e by 50% (IC50) at 0.12 mu M, a value 1000-times lower than the IC50 o f the product, ADP-ribose. The NAD glycohydrolase from Bungarus fascia tus venom was less sensitive to inhibition by ADP-HPD,exhibiting an IC 50 of 260 mu M. ADP-HPD did not inhibit either poly(ADP-ribose) polyme rase or NAD:arginine mono(ADP-ribosyl)-transferase A at inhibitor conc entrations up to 1 mM. At low ADP-HPD concentration, inhibition was th erefore shown to be highly specific for poly(ADP-ribose) glycohydrolas e,the hydrolytic enzyme in the metabolism of ADP-ribose polymers.