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Poly(adenosine diphosphate ribose) polymerase in Physarum polycephalum.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Brightwell, Miss Leech, Clifford O'farrell, M. K. Whish, William J. D. Shall, Sydney |
| Copyright Year | 1975 |
| Abstract | 1. The isolated nuclei of the slime mould Physarum polycephalum contain an enzyme that will incorporated [adenine-3H] NAD+ into an acid-insoluble product, which is shown to be poly(ADP-ribose). 2. This incorporation has an optimum pH of 8.2 and a temperature optimum below 10degreesC. 3. Optimum stimulation is given by 15 mM-Mg2+. 4. 2-Mercaptoethanol or dithiothreitol also stimulates the incorporation, the latter at an optimum concentration of about 1 mM. 5. Under optimum conditions the Km value for the reaction is 0.28 mM at 15degreesC. Nicotinamide inhibits the incorporation with a Ki of 5.7 muM. 6. Exogenous DNA stimulates the incorporation by about 100%. 7. Preincubation of the nuclei with deoxyribonuclease, but not with ribonuclease, almost completely inactivates the incorporation of NAD+. 8. The enzyme is unstable at both 0degrees and 15degreesC in the absence of dithiothreitol. The presence of dithiothreitol at a concentration of 1 mM stabilizes the enzyme at both these temperatures. 9. The activity of this enzyme per nucleus was shown in three separate experiments to fall by about one-half in early S phase and then to rise to its pre-mitotic value after about 3 h, that is in late S phase. 10. The possible physiological function of this enzyme system is discussed. |
| File Format | PDF HTM / HTML |
| DOI | 10.1042/bj1470119 |
| PubMed reference number | 239697 |
| Journal | Medline |
| Volume Number | 147 |
| Issue Number | 1 |
| Alternate Webpage(s) | http://www.biochemj.org/content/ppbiochemj/147/1/119.full.pdf |
| Alternate Webpage(s) | https://doi.org/10.1042/bj1470119 |
| Journal | The Biochemical journal |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
