Plant Physiol.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Eastmond, P. J.
Right arrow Articles by Rawsthorne, S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Eastmond, P. J.
Right arrow Articles by Rawsthorne, S.
Agricola
Right arrow Articles by Eastmond, P. J.
Right arrow Articles by Rawsthorne, S.

PLANT PHYSIOLOGY , Vol 114, Issue 3 851-856, Copyright © 1997 by American Society of Plant Biologists

BIOCHEMISTRY AND ENZYMOLOGY

Evidence That a Malate/Inorganic Phosphate Exchange Translocator Imports Carbon across the Leucoplast Envelope for Fatty Acid Synthesis in Developing Castor Seed Endosperm

P. J. Eastmond, D. T. Dennis and S. Rawsthorne
Department of Brassica and Oilseeds Research, John Innes Centre, Norwich, NR4 7UH, United Kingdom (P.J.E., S.R.)

In this study we examined the processes by which malate and pyruvate are taken up across the leucoplast envelope for fatty acid synthesis in developing castor (Ricinus communis L.) seed endosperm. Malate was taken up by isolated leucoplasts with a concentration dependence indicative of protein-mediated transport. The maximum rate of malate uptake was 704 [plus or minus] 41 nmol mg-1 protein h-1 and the Km was 0.62 [plus or minus] 0.08 mM. In contrast, the rate of pyruvate uptake increased linearly with respect to the substrate concentration and was 5-fold less than malate at a concentration of 5 mM. Malate uptake was inhibited by inorganic phosphate (Pi), glutamate, malonate, succinate, 2-oxoglutarate, and n-butyl malonate, an inhibitor of the mitochondrial malate/Pi-exchange translocator. Back-exchange experiments confirmed that malate was taken up by leucoplasts in counterexchange for Pi. The exchange stoichiometry was 1:1. The rate of malate-dependent fatty acid synthesis by isolated leucoplasts was 3-fold greater than from pyruvate at a concentration of 5 mM and was inhibited by n-butyl malonate. It is proposed that leucoplasts from developing castor endosperm contain a malate/Pi translocator that imports malate for fatty acid synthesis. This type of dicarboxylate transport activity has not been identified previously in plastids.


This article has been cited by other articles:


Home page
 J Exp BotHome page
T. Endo, Y. Mihara, T. Furumoto, H. Matsumura, Y. Kai, and K. Izui
Maize C4-form phosphoenolpyruvate carboxylase engineered to be functional in C3 plants: mutations for diminished sensitivity to feedback inhibitors and for increased substrate affinity
J. Exp. Bot., May 1, 2008; 59(7): 1811 - 1818.
[Abstract] [Full Text] [PDF]

Home page
 Plant Physiol.Home page
M. A. Tronconi, H. Fahnenstich, M. C. Gerrard Weehler, C. S. Andreo, U.-I. Flugge, M. F. Drincovich, and V. G. Maurino
Arabidopsis NAD-Malic Enzyme Functions As a Homodimer and Heterodimer and Has a Major Impact on Nocturnal Metabolism
Plant Physiology, April 1, 2008; 146(4): 1540 - 1552.
[Abstract] [Full Text] [PDF]

Home page
 Plant Physiol.Home page
R. G. Uhrig, B. O'Leary, H. E. Spang, J. A. MacDonald, Y.-M. She, and W. C. Plaxton
Coimmunopurification of Phosphorylated Bacterial- and Plant-Type Phosphoenolpyruvate Carboxylases with the Plastidial Pyruvate Dehydrogenase Complex from Developing Castor Oil Seeds
Plant Physiology, March 1, 2008; 146(3): 1346 - 1357.
[Abstract] [Full Text] [PDF]

Home page
 Plant Physiol.Home page
K. E. Tripodi, W. L. Turner, S. Gennidakis, and W. C. Plaxton
In Vivo Regulatory Phosphorylation of Novel Phosphoenolpyruvate Carboxylase Isoforms in Endosperm of Developing Castor Oil Seeds
Plant Physiology, October 1, 2005; 139(2): 969 - 978.
[Abstract] [Full Text] [PDF]

Home page
 Plant Physiol.Home page
M. C. G. Wheeler, M. A. Tronconi, M. F. Drincovich, C. S. Andreo, U.-I. Flugge, and V. G. Maurino
A Comprehensive Analysis of the NADP-Malic Enzyme Gene Family of Arabidopsis
Plant Physiology, September 1, 2005; 139(1): 39 - 51.
[Abstract] [Full Text] [PDF]

Home page
 J Exp BotHome page
R. Pleite, M. J. Pike, R. Garces, E. Martinez-Force, and S. Rawsthorne
The sources of carbon and reducing power for fatty acid synthesis in the heterotrophic plastids of developing sunflower (Helianthus annuus L.) embryos
J. Exp. Bot., May 1, 2005; 56(415): 1297 - 1303.
[Abstract] [Full Text] [PDF]

Home page
 J Exp BotHome page
S. E. Kubis, M. J. Pike, C. J. Everett, L. M. Hill, and S. Rawsthorne
The import of phosphoenolpyruvate by plastids from developing embryos of oilseed rape, Brassica napus (L.), and its potential as a substrate for fatty acid synthesis
J. Exp. Bot., July 1, 2004; 55(402): 1455 - 1462.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
J. Schwender, J. B. Ohlrogge, and Y. Shachar-Hill
A Flux Model of Glycolysis and the Oxidative Pentosephosphate Pathway in Developing Brassica napus Embryos
J. Biol. Chem., August 8, 2003; 278(32): 29442 - 29453.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
J. D. Blonde and W. C. Plaxton
Structural and Kinetic Properties of High and Low Molecular Mass Phosphoenolpyruvate Carboxylase Isoforms from the Endosperm of Developing Castor Oilseeds
J. Biol. Chem., March 28, 2003; 278(14): 11867 - 11873.
[Abstract] [Full Text] [PDF]

Home page
 Plant Physiol.Home page
P. J. Eastmond and S. Rawsthorne
Coordinate Changes in Carbon Partitioning and Plastidial Metabolism during the Development of Oilseed Rape Embryos
Plant Physiology, March 1, 2000; 122(3): 767 - 774.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
ASPB Publications PLANT PHYSIOLOGY THE PLANT CELL
Copyright © 1997 by the American Society of Plant Biologists