NADPH: a stimulatory cofactor for nitric oxide-induced ADP-ribosylation reaction.
An endogenous ADP-ribosyltransferase is present in the cytosolic fraction of human platelets. Agents known to release nitric oxide activated this ADP-ribosylation reaction in a cGMP-independent fashion. This enzymatic activity was further enhanced by the addition of NADPH to the platelet cytosolic fraction. Interestingly, NADPH was unable to replace DTT, which has been described as an essential cofactor. Our results indicate that NADPH is a stimulatory factor of the endogenous ADP-ribosylation reaction. NADPH shifts the dose-response curve of NO to the left and possibly increases, in this way, the ADP-ribosylation reaction under physiological conditions.
Brüne
B
B
Faculty of Biology, Department of Biological Chemistry, University of Konstanz, F.R.G.
Dimmeler
S
S
Lapetina
E G
EG
D000246:Adenosine Diphosphate Ribose / Q000097:blood*; D001792:Blood Platelets / Q000378:metabolism*; D001798:Blood Proteins / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D004229:Dithiothreitol / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D009243:NAD / Q000097:blood*; D009249:NADP / Q000494:pharmacology*; D009569:Nitric Oxide / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology; D010084:Oxidation-Reduction; D011065:Poly(ADP-ribose) Polymerases / Q000097:blood*
D001798:Blood Proteins; D009243:NAD; D009599:Nitroprusside; D000246:Adenosine Diphosphate Ribose; D009569:Nitric Oxide; D009249:NADP; D011065:Poly(ADP-ribose) Polymerases; D004229:Dithiothreitol