Identification in human erythrocytes of mono(ADP-ribosyl) protein hydrolase that cleaves a mono(ADP-ribosyl) Gi linkage

AbstractA novel enzymatic activity, the hydrolysis of linkages between mono(ADP-ribose) and cysteine residues in Gi prepared by eukaryotic ADP-ribosyl-transferase C [(1988) J. Biol. Chem. 263, 5485-5489] was found in the cytosol of human erythrocytes. The mono(ADP-ribosyl) Gi hydrolase, tentatively named ADP-ribosyI protein hydrolase C was partially purified by sequential chromatographies on DEAE-cellulose and Blue Sepharose. This enzyme catalyzes the release of ADP-ribose from mono(ADP-ribosyl) Gi Its activity was enhanced by Ca2+ and inhibited by ADP-ribose. The presence of this enzyme in eukaryotic cells suggests that endogenous mono(ADP-ribosyl)ation of Gi is a reversible post-translational modification