| | 1 | Author
| SujataR M Ishra, SurendraChandra Sabat | Requires cookie* | | | Title
| Effect of Magnesium and Calcium Ions on the Photoelectron Transport Activity of Low-Salt Suspended Hydrilla verticillata Thylakoids: Possible Sites of Cation Interaction  | | | | Abstract
| Stimulatory effect o f divalent cations like calcium (Ca2+) and magnesium (M g2+) was inves tigated on electron transport activity of divalent cation deficient low-salt suspended (LS) thylakoid preparation from a submerged aquatic angiosperm, Hydrilla verticillata. Both the cations stimulated electron transport activity of LS-suspended thylakoids having an intact water oxidation complex. But in hydroxylamine (N H 2OH) -or alkaline Tris -washed thyla koid preparations (with the water oxidation enzyme impaired), only Ca2+ dependent stimula tion of electron transport activity was found. The apparent K m of Ca2+ dependent stimulation of electron flow from H 20 (endogenous) or from artificial electron donor (exogenous) to dichlorophenol indophenol (acceptor) was found to be identical. Calcium supported stimula tion of electron transport activity in N H 2OH -or Tris -washed thylakoids was electron donor selective, i.e., Ca2+ ion was only effective in electron flow with diphenylcarbazide but not with N H 2OH as electron donor to photosystem II. A magnesium effect was observed in thylakoids having an intact water oxidation complex and the ion became unacceptable in N H 2OH -or Tris -washed thylakoids. Indirect experimental evidences have been presented to suggest that Mg2+ interacts with the water oxidation complex, while the Ca2+ interaction is localized betw een Y z and reaction center of photosystem II. | | | |
Reference
| Z. Naturforsch. 53c, 849—8 (1998); received March 16/May 12 1998 | | | |
Published
| 1998 | | | |
Keywords
| Aquatic Angiosperm, Divalent Cation, Electron Transport, Fluorescence, Hydrilla verticillata | | | |
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| default:Reihe_C/53/ZNC-1998-53c-0849.pdf | | | | Identifier
| ZNC-1998-53c-0849 | | | | Volume
| 53 | |
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