| | 1 | Author
| Jacek Wierzchowski, David Shugar | Requires cookie* | | | Title
| Sensitive Fluorimetric Assay for Adenosine Deaminase with Formycin as Substrate; and Substrate and Inhibitor Properties of some Pyrazolopyrimidine and Related Analogues  | | | | Abstract
| The nucleoside antibiotic formycin, 7-amino-3-(/?-D-ribofuranosyl)pyrazolo(4,3-d)pyrimidine, a structural analogue of adenosine, is deaminated about 10-fold faster by adenosine deaminase than adenosine itself, and is therefore a superior substrate for both routine assays and kinetic studies with the purified enzyme. The luminescence properties o f formycin have been profited from to develop a fluorimetric assay for adenosine deaminase which is considerably more sensi tive than the spectrophotometric procedure widely employed with adenosine as substrate. Exam ples are presented of its application to routine assays of adenosine deaminase levels in cellular extracts, as well as to kinetic studies with the purified enzyme, including the properties o f some pyrazolopyrimidine and purine substrates and inhibitors. | | | |
Reference
| Z. Naturforsch. 38c, 67—7 (1983); received August 23 1982 | | | |
Published
| 1983 | | | |
Keywords
| Formycin, Pyrazolopyrimidines, Adenosine Deaminase, Fluorimetric Assay, Inhibitors | | | |
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| default:Reihe_C/38/ZNC-1983-38c-0067.pdf | | | | Identifier
| ZNC-1983-38c-0067 | | | | Volume
| 38 | |
| 2 | Author
| Friedrich Jiittner, O. Ttm Ar Bogenschütz | Requires cookie* | | | Title
| Geranyl Derivatives as Inhibitors o f the Carotenogenesis in Synechococcus PCC 6911 (Cyanobacteria) | | | | Abstract
| The ability of several geranyl derivatives to inhibit carotenoid synthesis in Synechococcus (Cyanobacteria) was measured using a cyanobacterial bioassay. The inhibitory activity o f differ ent molecules varied according to chain length and substituents. Pseudoionone, famesyl acetate, geranyl acetate, geranial and farnesol proved to be the most active derivatives tested. 6-Methylhept-5-en-2-one, farnesyl acetone, linalool and geranyl linalool exhibited no effect when employed in concentrations as high as 100 ppm. Besides phytofluene, C-carotene was accumu lated after application o f sublethal amounts o f active geranyl derivatives. Cell growth and chlorophyll a synthesis were only slightly affected under conditions were carotenoid synthesis was markedly inhibited. | | | |
Reference
| Z. Naturforsch. 38c, 387 (1983); received January 26 1983 | | | |
Published
| 1983 | | | |
Keywords
| Inhibitors, Carotenoid Synthesis, Pseudoionone, Famesol, Famesyl Acetate | | | |
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| default:Reihe_C/38/ZNC-1983-38c-0387.pdf | | | | Identifier
| ZNC-1983-38c-0387 | | | | Volume
| 38 | |
| 3 | Author
| W. S. Cohen, J. R. Barton | Requires cookie* | | | Title
| The Use of 0 2-Evolving Subchloroplast Particles to Study Acceptor and Inhibitor Sites on the Reducing Side of Photosystem II | | | | Abstract
| Photosystem II particles that retain the ability to evolve 0 2 have been used to exam ine acceptor and inhibitor sites in the photosynthetic electron transfer chain between Q and plasto-quinone. Employing the water to dichlorobenzoquinone reaction to assay photosystem II activity, we have demonstrated that electron transport in thylakoids and particles is equally sensitive to inhibition by D C M U , dinoseb, metribuzin, H Q N O and DBMIB. Based on differential sensitivity to inhibition by D C M U vs. H Q N O or DBMIB, we suggest that when synthetic quinones, e.g. 2,6-dichlorobenzoquinone operate as Hill reagents in particles they are reduced primarily by the plastoquinone pool. W hen synthetic quinones, e.g. 5,6-m ethylenedioxy-2,3-dim ethyl benzoquinone act as autoxidizable acceptors they accept electron from the Q /B com plex at a point that is located between the D C M U and H Q N O (DBM IB) inhibition sites. | | | |
Reference
| Z. Naturforsch. 38c, 793—798 (1983); received April 26 1983 | | | |
Published
| 1983 | | | |
Keywords
| Thylakoids, Photosystem II Particles, Q uinones, Inhibitors, Electron Transfer | | | |
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| default:Reihe_C/38/ZNC-1983-38c-0793.pdf | | | | Identifier
| ZNC-1983-38c-0793 | | | | Volume
| 38 | |
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