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Media type:
E-Article
Title:
Spermidine Uptake by Mitochondria of Helianthus tuberosus
Contributor:
Bagni, Nello;
Zannoni, Davide
Published:
American Society of Plant Physiologists, 1990
Published in:
Plant Physiology, 92 (1990) 3, Seite 690-695
Language:
English
ISSN:
0032-0889;
1532-2548
Origination:
Footnote:
Description:
In the present work evidence is provided that spermidine, a polyamine largely present in plant tissues, may be transported, at physiological concentrations, into the matrix space of mitochondria isolated from tubers of Helianthus tuberosus L. cv OB1 (Jerusalem artichoke). It is concluded that the movement of spermidine strictly depends on membrane potential, since it is drastically blocked by valinomycin and only slightly sensitive to nigericin. Mg2+ and K+ inhibit the transport of spermidine in line with the general concept that these cations compete for the same binding sites on the mitochondrial membrane. In contrast to previous data on mammalian mitochondria, spermidine uptake by plant mitochondria does not depend on the presence of inorganic phosphate. This latter result, along with evidence that Ca2+ does not affect accumulation of spermidine, indicates that the control of the polyamine uptake mechanism in plant mitochondria is distinct from that of mammalian systems.