Plant Physiol. Tips for Better Browsing
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 Khozin, I.
Right arrow Articles by Cohen, Z.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Khozin, I.
Right arrow Articles by Cohen, Z.
Agricola
Right arrow Articles by Khozin, I.
Right arrow Articles by Cohen, Z.

PLANT PHYSIOLOGY , Vol 114, Issue 1 223-230, Copyright © 1997 by American Society of Plant Biologists

BIOCHEMISTRY AND ENZYMOLOGY

Elucidation of the Biosynthesis of Eicosapentaenoic Acid in the Microalga Porphyridium cruentum (II. Studies with Radiolabeled Precursors)

I. Khozin, D. Adlerstein, C. Bigongo, Y. M. Heimer and Z. Cohen
The Laboratory for Microalgal Biotechnology (I.K., D.A. C.B., Z.C.), and the Albert Katz Center for Desert Agrobiology (Y.M.H.), Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sde-Boker Campus 84990, Israel

In the course of the study of the biosynthesis of the fatty acid eicosapentaenoic acid (EPA) in the microalga Porphyridium cruentum, cells were pulse-labeled with various radiolabeled fatty acid precursors. Our data show that the major end products of the biosynthesis are EPA-containing galactolipids of a eukaryotic and prokaryotic nature. The prokaryotic molecular species contain EPA and arachidonic acid at the sn-1 position and C16 fatty acids, mainly 16:0, at the sn-2 positions, whereas in the eukaryotic species both positions are occupied by EPA or arachidonic acid. However, we suggest that both the eukaryotic and prokaryotic molecular species are formed in two pathways, [omega]6 and [omega]3, which involve cytoplasmic and chloroplastic lipids. In the [omega]6 pathway, cytoplasmic 18:2-phosphatidylcholine (PC) is converted to 20:4[omega]6-PC by a sequence that includes a [delta]6 desaturase, an elongation step, and a [delta]5 desaturase. In the minor [omega]3 pathway, 18:2-PC is presumably desaturated to 18:3[omega]3, which is sequentially converted by the enzymatic sequence of the [omega]6 pathway to 20:5[omega]3-PC. The products of both pathways are exported, as their diacylglycerol moieties, to the chloroplast to be galactosylated into their respective monogalactosyldiacylglycerol molecular species. The 20:4[omega]6 in both eukaryotic and prokaryotic monogalactosyldiacylglycerol can be further desaturated to EPA by a chloroplastic [delta]17 ([omega]3) desaturase.


This article has been cited by other articles:


Home page
 J. Bacteriol.Home page
H.-P. Cheng and G. C. Walker
Succinoglycan Is Required for Initiation and Elongation of Infection Threads during Nodulation of Alfalfa by Rhizobium meliloti
J. Bacteriol., October 1, 1998; 180(19): 5183 - 5191.
[Abstract] [Full Text]


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