This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Smith, R. G. Articles by Turpin, D. H. Search for Related Content PubMed PubMed Citation Articles by Smith, R. G. Articles by Turpin, D. H. Agricola Articles by Smith, R. G. Articles by Turpin, D. H.

Metabolism and Enzymology

Malate- and Pyruvate-Dependent Fatty Acid Synthesis in Leucoplasts from Developing Castor Endosperm ¹

Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4

Leucoplasts were isolated from the endosperm of developing castor (Ricinis communis) endosperm using a discontinuous Percoll gradient. The rate of fatty acid synthesis was highest when malate was the precursor, at 155 nanomoles acetyl-CoA equivalents per milligram protein per hour. Pyruvate and acetate also were precursors of fatty acid synthesis, but the rates were approximately 4.5 and 120 times less, respectively, than when malate was the precursor. When acetate was supplied to leucoplasts, exogenous ATP, NADH, and NADPH were required to obtain maximal rates of fatty acid synthesis. In contrast, the incorporation of malate and pyruvate into fatty acids did not require a supply of exogenous reductant. Further, the incorporation of radiolabel into fatty acids by leucoplasts supplied with radiolabeled malate, pyruvate, or acetate was reduced upon coincubation with cold pyruvate or malate. The data suggest that malate and pyruvate may be good in vivo sources of carbon for fatty acid synthesis and that, in these preparations, leucoplast fatty acid synthesis may be limited by activity at or downstream of the acetyl-CoA carboxylase reaction.

³ Present address: Department of Biology, Queen's University, Kingston, Ontario, K7L 3N6, Canada.

¹ Supported by the Natural Sciences and Engineering Council of Canada.

This article has been cited by other articles:

				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]

				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]

				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]

				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]

				S. A. Ruuska, J. Schwender, and J. B. Ohlrogge The Capacity of Green Oilseeds to Utilize Photosynthesis to Drive Biosynthetic Processes Plant Physiology, September 1, 2004; 136(1): 2700 - 2709. [Abstract] [Full Text] [PDF]

				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]

				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]

				M. Jeanneau, J. Vidal, A. Gousset-Dupont, B. Lebouteiller, M. Hodges, D. Gerentes, and P. Perez Manipulating PEPC levels in plants J. Exp. Bot., September 1, 2002; 53(376): 1837 - 1845. [Abstract] [Full Text] [PDF]

				J. Ke, R. H. Behal, S. L. Back, B. J. Nikolau, E. S. Wurtele, and D. J. Oliver The Role of Pyruvate Dehydrogenase and Acetyl-Coenzyme A Synthetase in Fatty Acid Synthesis in Developing Arabidopsis Seeds Plant Physiology, June 1, 2000; 123(2): 497 - 508. [Abstract] [Full Text]

				D. Rangasamy and C. Ratledge Compartmentation of ATP:Citrate Lyase in Plants Plant Physiology, April 1, 2000; 122(4): 1225 - 1230. [Abstract] [Full Text]

				D. Rangasamy and C. Ratledge Genetic Enhancement of Fatty Acid Synthesis by Targeting Rat Liver ATP:Citrate Lyase into Plastids of Tobacco Plant Physiology, April 1, 2000; 122(4): 1231 - 1238. [Abstract] [Full Text]

				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]

				M. Berkemeyer, R. Scheibe, and O. Ocheretina A Novel, Non-redox-regulated NAD-dependent Malate Dehydrogenase from Chloroplasts of Arabidopsis thaliana L. J. Biol. Chem., October 23, 1998; 273(43): 27927 - 27933. [Abstract] [Full Text] [PDF]

				N. Focks and C. Benning wrinkled1: A Novel, Low-Seed-Oil Mutant of Arabidopsis with a Deficiency in the Seed-Specific Regulation of Carbohydrate Metabolism Plant Physiology, September 1, 1998; 118(1): 91 - 101. [Abstract] [Full Text]