title: Poly(ADP-ribose) polymerase in plant nuclei.
abstract: We show that poly(ADP-ribose) polymerase is present in maize, pea and wheat nuclei. We have identified the enzyme product as poly(ADP-ribose) by purification and electrophoresis on a DNA sequencing gel. This reveals a polymer ladder consisting of up to 45 residues. The polymer product from maize, after digestion with snake venom phosphodiesterase, gave only 5'-AMP and (phosphoribosyl)-AMP; the mean chain length of the polymer was 5 and 11 residues in two separate experiments. The optimum pH of the plant enzyme is greater than pH 7.0 in pea, wheat and maize; the optimum temperature for enzyme activity is approximately 15 degrees C. The Km for NAD+ for the enzyme from maize is estimated to be approximately 50 microM under optimal conditions. Several compounds (nicotinamide, deoxythymidine, 3-aminobenzamide, 3-methoxybenzamide and 5-bromodeoxyuridine) that specifically inhibit the animal enzyme also inhibit the enzyme from plants. The ratio of the IC50 for 5-bromodeoxyuridine to the IC50 for 3-aminobenzamide in maize is similar to that of the animal enzyme indicating that the enzyme involved is poly(ADP-ribose) polymerase and not mono(ADP-ribosyl) transferase. SDS gel electrophoresis and gel filtration analysis of a crude extract of maize nuclei indicate a molecular mass for poly(ADP-ribose) polymerase of approximately 114 kDa.
authors.affiliation: Department of Biology, University of Essex, England.
authors.forename: Y M
authors.initials: YM
authors.lastname: Chen
authors.forename: S
authors.initials: S
authors.lastname: Shall
authors.forename: M
authors.initials: M
authors.lastname: O'Farrell
mesh_terms: D036002:ADP Ribose Transferases; D002467:Cell Nucleus / Q000201:enzymology; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D007887:Fabaceae / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D015151:Immunoblotting; D008970:Molecular Weight; D009243:NAD / Q000378:metabolism; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D010944:Plants / Q000201:enzymology*; D010946:Plants, Medicinal; D011064:Poly Adenosine Diphosphate Ribose / Q000096:biosynthesis; D011065:Poly(ADP-ribose) Polymerases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D013696:Temperature; D014908:Triticum / Q000201:enzymology; D003313:Zea mays / Q000201:enzymology
chemical_list: D009243:NAD; D011064:Poly Adenosine Diphosphate Ribose; D036002:ADP Ribose Transferases; D011065:Poly(ADP-ribose) Polymerases; D010727:Phosphoric Diester Hydrolases