Figure 1
The reversible ADP-ribosylation reaction. ARTs and PARPs catalyse the transfer of an ADP-ribose moiety from NAD onto specific amino-acid residues or onto ADP-ribose, respectively, thereby releasing nicotinamide. The reverse reaction is catalysed by ARHs or PARGs through the hydrolysis of the [alpha]-glycosidic bond between ADP-ribose and the side chain. X can be Arg, Asp, Glu, Asn, Cys, diphthamide or ADP-ribose. For mono-ADP-ribosylation R and R' are hydroxyl groups, while for poly-ADP-ribosylation ADP-ribose can be attached to the R site (elongation) or to the R' site (branching).  [article HTML]

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