Poly(Adenosine Diphosphate Ribose) in Physarum polycephalum (original) (raw)

ADP-ribosylation in isolated nuclei of Physarum polycephalum

Biochemical Journal, 1988

ADP-ribosylation of histones and non-histone nuclear proteins was studied in isolated nuclei during the naturally synchronous cell cycle of Physarum polycephalum. Aside from ADP-ribosyltransferase (ADPRT) itself, histones and high mobility group-like proteins are the main acceptors for ADP-ribose. The majority of these ADP-ribose residues is NH2OH-labile. ADP-ribosylation of the nuclear proteins is periodic during the cell cycle with maximum incorporation in early to mid G2-phase. In activity gels two enzyme forms with Mr of 115,000 and 75,000 can be identified. Both enzyme forms are present at a constant ratio of 3:1 during the cell cycle. The higher molecular mass form cannot be converted in vitro to the low molecular mass form, excluding an artificial degradation during isolation of nuclei. The ADPRT forms were purified and separated by h.p.l.c. The low molecular mass form is inhibited by different ADPRT inhibitors to a stronger extent and is the main acceptor for auto-ADP-ribosy...

ADP-ribosyltransferase in isolated nuclei during the cell cycle of Physarum polycephalum

The Biochemical journal, 1985

ADP-ribosyltransferase was measured in isolated nuclei of Physarum polycephalum. Activity was determined with and without exogenous DNA and histones. During the synchronous cell cycle the activity measured with exogenous substrates exhibited a typical peak enzyme pattern with a maximum of activity in S-phase, whereas activity measured without exogenous substrates displayed a step enzyme pattern. Both activities doubled in each cell cycle.

Endonuclease activity in nuclei of Physarum polycephalum Partial purification and characterization

1977

An endonuclease, present in the microplasmodia of Physarum polycephalum, has been partially purified from isolated nuclei by DEAE-cellulose and Sephadex G-75 chromatography. 1. The endonuclease produced single-strand scissions in double-stranded DNA which resulted in the generation of 5'-phosphoryl and 3'-hydroxyl termini. No activity was observed with single-stranded DNA as substrate. 2. The pH optimum was approximately 8.5. 3. Divalent cations were essential for enzyme activity. MnC12 and MgC12 gave maximal activity. CaC12, ZnCI2 or CoC12 did not activate the enzyme. 4. The endonuclease activity was highly sensitive to monovalent cations. 5. Endonuclease activity was found in two forms after gel filtration: an activity in a homogeneous peak with a molecular weight of approx. 20 000, and an activity that had a heterogeneous molecular weight and which was isolated in a complex with DNA. A possible function of the endonuclease in DNA replication is discussed.

Alkaline nucleases in Physarum polycephalum

1980

Grsag uil ik iedereen bedanker die op de een ûf andere manier hoeft bijgedragen aan de totstandkoming van dit proefschrift. Mijn ouders die mij de mogelijkheid hebben gegeuen om mijzelf te ontplooien. Alle medeuerkers van de afdeling Chemische Cytologie. Jullie hebben mij geholpen met jullie ideën, met jullie geduld als ik mijn vaak uilde ideën of luidkeels enthousiasme uilde spuien, en met jullie inzet bij het uerk en bij de ontspanning aan de pingpong tafel. Alle studenten die in de afgelopen vijf jaren hun onderzoek hebben uillen richten op Physarum en uier ideën en uerk hebben bijgedragen aan de inhoud van dit proefschri ft. Alle medeuerkers van de afdeling Moleculaire Biologie te Mijmegen (Hoofd : Prof.Dr.3.G.G.Schoenmakers) die mij vaak onderdak en steun hebben gegeven. Alle deelnemers aan de Physarum Uorkshops in Rüttihubelbad (1976), Scefeld (1979) en Quebec (1979) voor hun stimulerende diskussies, en meer in het bijzonder Prof.

A new method for the assay of poly(adenosine diphosphate ribose) glycohydrolase activity

Analytical Biochemistry, 1975

Rib was estimated by measuring the radioactivity in aliquots of formic acid extract. Oligomers or polymers of ADP-Rib can be utilized as substrates since the reaction rates were the same with either compound. A method to determine phosphodiesterase and glycohydrolase activities was established. These two enzymic activities were distinguished by treating the products of the reactions with alkaline phosphatase and by differential extraction of the adsorbed reaction products on Dowex with 0.5 M and 6 M formic acid. Eukaryotic cells contain a nuclear enzyme that catalyzes the conversion of NAD into poly(ADP-Rib)' with the concomitant elimination of nicotinamide (I-5). The repeating units of ADP-Rib are linked together by a glycosidic bond of ribosyl-1,2-ribose (3,5). The characteristics of the polymer and properties of the polymerizing enzyme have been reported (6-9). This biopolymer is hydrolyzed by two types of enzymes, namely, phosphodiesterase and glycohydrolase. The pyrophosphate bond is hydrolyzed by venom and rat-liver nuclear phosphodiesterase (2,4,10,11). The products of the reaction are AMP, PR-AMP and ribose-5'-phosphate. The chain length of the polymer can be calculated from the relative amounts of PR-AMP and AMP (12). Recently, a new enzymatic reaction has been reported which splits the ribose-ribose linkage between two ADP-Rib units with the release of only ADP-Rib

Advances in Enzymology and Related Areas of Molecular Biology; volume 51

FEBS Letters, 1981

I. Introduction 11. General Considerations A. Function of the Enzyme B. Occurrence and Purification of Succinyl CoA Synthetase C. Substrate Specificity 1. Succinate 2. Nucleoside Triphosphate and Diphosphate 3. Coenzyme A 4. Inorganic Phosphate 5. Divalent Metal Ion D. Michaelis Constants of Substrates Mechanism of the Succinyl CoA Synthetase Reaction A. The Phosphorylated Enzyme B. High Energy Nonphosphorylated Form of the Enzyme. Evidence C. Evidence for Intermediary Formation of Enzyme-Bound Succinyl Structural Studies of the Enzyme V. Conclusion Acknowledgement References 111. for I t s Noninvolvement in the Net Catalytic Reaction Phosphate IV. 183 184 185 185 185 * Succinate: CoA ligase (ADP), E C 6.2.1.5 and (GDP), EC 6.2.1.4, also known as the succinate-phosphorylating enzyme, P-enzyme, and succinic thiokinase.