title: Novel enzyme from rat liver that cleaves an ADP-ribosyl histone linkage.
abstract: A novel enzyme that splits a bond between ADP-ribose and histone was discovered and partially purified from rat liver cytosol. The 105,000 X g supernatant of rat liver homogenate was precipitated by 45% saturated ammonium sulfate and then chromatographed on a DEAE-cellulose column. The enzyme activity was eluted in a single peak at about 0.2 M NaCl and clearly separated from poly(ADP-ribose) glycohydrolase which came out at 0.13 M NaCl. In contrast to the latter enzyme, this new enzyme catalyzed the spliting of a linkage between ADP-ribose and a protein portion in mono ADP-ribosylated histone H2B but little, if any, of the glycosidic ribosyl(1"-2') ribose bonds within poly(ADP-ribose). Analysis of the reaction product by paper chromatography and Dowex 1 column chromatography indicated that the split product contained the ADP-ribose moiety but was not exactly identical with ADP-ribose. Available evidence suggested that it was either an altered ADP-ribose molecule produced by a structural rearrangement or ADP-ribose itself linked to an unidentified compound. The enzyme had a pH optimum of about 6.0 and was inhibited by 80-90% in the presence of 5 mM ADP-ribose.
mesh_terms: D000818:Animals; D003600:Cytosol / Q000201:enzymology; D006026:Glycoside Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D006657:Histones / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D009702:Nucleoside Diphosphate Sugars / Q000378:metabolism*; D011064:Poly Adenosine Diphosphate Ribose / Q000378:metabolism*; D051381:Rats
chemical_list: D006657:Histones; D009702:Nucleoside Diphosphate Sugars; D011064:Poly Adenosine Diphosphate Ribose; D006026:Glycoside Hydrolases