Sulfide-induced oxygen uptake by isolated spinach chloroplasts catalyzed by photosynthetic electron transport |
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Authors: | L. J. de Kok C. R. Thompson P. J. C. Kuiper |
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Affiliation: | Dept. of Plant Physiology, Univ. of Groningen, P.O. Box 14, 9750 AA Haren (Gn), The Netherlands;C. R. Thompson, Statewide Air Pollution Research Center, Univ. of California, Riverside, CA 92521, USA. |
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Abstract: | In addition to an inhibitory effect on the photoreduction of NADP+ by isolated spinach chloroplasts ( Spinacea oleracea L. cv. Melody Hybrid), sulfide initiated oxygen uptake by chloroplasts upon illumination, both in presence and absence of an electron acceptor. Sulfide-induced oxygen uptake was sensitive to DCMU demonstrating the involvement of photosynthetic electron transport. Addition of superoxide dismutase to the chloroplast suspension prevented the sulfide-induced oxygen uptake, which indicated that sulfide may be oxidized by the chloroplast, its oxidation being initiated by superoxide formed upon illumination (at the reducing side of PSI). Tris-induced inhibition of NADP+ photo-reduction could not be abolished by sulfide, which indicated that sulfide could not act as an electron donor for PSI. |
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Keywords: | Hydrogen sulfide superoxide superoxide dismutase |
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