|
PLANT PHYSIOLOGY , Vol 110, Issue 3 923-931, Copyright © 1996 by American Society of Plant Biologists
|
BIOCHEMISTRY AND ENZYMOLOGY |
Cholinephosphotransferase and Diacylglycerol Acyltransferase (Substrate Specificities at a Key Branch Point in Seed Lipid Metabolism)
G. Vogel and J. Browse
Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340
Many oilseed plants accumulate triacylglycerols that contain unusual fatty
acyl structures rather than the common 16- and 18-carbon fatty acids found
in membrane lipids of these plants. In vitro experiments demonstrate that
triacylglycerols are synthesized via diacylglycerols in microsomal
preparations and that this same sub-cellular fraction is the site for the
synthesis of phosphatidylcholine, which in seeds is synthesized from
diacylglycerol by CDP-choline: diacylglycerol cholinephosphotransferase. In
microsomes from Cuphea lanceolata, a plant that accumulates fatty acids
with 10 carbons and no double bonds (10:0) in its oil, the diacylglycerol
acyltransferase exhibited 4-fold higher activity with 10:0/10:0 molecular
species of diacylglycerol than with molecular species containing 18-carbon
fatty acids. In castor bean (Ricinus communis), which accumulates oil
containing ricinoleic acid, diricinoleoyldiacylglycerol was the favored
substrate for triacylglycerol synthesis. In contrast to these modest
specificities of the diacylglycerol acyltransferases, the
cholinephosphotransferases from these plants and from safflower (Carthamus
tinctorius) and rapeseed (Brassica napus) showed little or no specificity
across a range of different diacylglycerol substrates. Consideration of
these results and other data suggests that the targeting of unusual fatty
acids to triacylglycerol synthesis and their exclusion from membrane lipids
are not achieved on the basis of the diacylglycerol substrate specificities
of the enzymes involved and may instead require the spatial separation of
two different diacylglycerol pools.
This article has been cited by other articles:

|
 |

|
 |
 
C. Lu, Z. Xin, Z. Ren, M. Miquel, and J. Browse
An enzyme regulating triacylglycerol composition is encoded by the ROD1 gene of Arabidopsis
PNAS,
November 3, 2009;
106(44):
18837 - 18842.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
P. D. Bates, T. P. Durrett, J. B. Ohlrogge, and M. Pollard
Analysis of Acyl Fluxes through Multiple Pathways of Triacylglycerol Synthesis in Developing Soybean Embryos
Plant Physiology,
May 1, 2009;
150(1):
55 - 72.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
J. M. Shockey, S. K. Gidda, D. C. Chapital, J.-C. Kuan, P. K. Dhanoa, J. M. Bland, S. J. Rothstein, R. T. Mullen, and J. M. Dyer
Tung Tree DGAT1 and DGAT2 Have Nonredundant Functions in Triacylglycerol Biosynthesis and Are Localized to Different Subdomains of the Endoplasmic Reticulum
PLANT CELL,
September 1, 2006;
18(9):
2294 - 2313.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
A. Milcamps, A. W. Tumaney, T. Paddock, D. A. Pan, J. Ohlrogge, and M. Pollard
Isolation of a Gene Encoding a 1,2-Diacylglycerol-sn-acetyl-CoA Acetyltransferase from Developing Seeds of Euonymus alatus
J. Biol. Chem.,
February 18, 2005;
280(7):
5370 - 5377.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
A. Abbadi, F. Domergue, J. Bauer, J. A. Napier, R. Welti, U. Zahringer, P. Cirpus, and E. Heinz
Biosynthesis of Very-Long-Chain Polyunsaturated Fatty Acids in Transgenic Oilseeds: Constraints on Their Accumulation
PLANT CELL,
October 1, 2004;
16(10):
2734 - 2748.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
F. Beisson, A. J.K. Koo, S. Ruuska, J. Schwender, M. Pollard, J. J. Thelen, T. Paddock, J. J. Salas, L. Savage, A. Milcamps, et al.
Arabidopsis Genes Involved in Acyl Lipid Metabolism. A 2003 Census of the Candidates, a Study of the Distribution of Expressed Sequence Tags in Organs, and a Web-Based Database
Plant Physiology,
June 1, 2003;
132(2):
681 - 697.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
C. Jako, A. Kumar, Y. Wei, J. Zou, D. L. Barton, E. M. Giblin, P. S. Covello, and D. C. Taylor
Seed-Specific Over-Expression of an Arabidopsis cDNA Encoding a Diacylglycerol Acyltransferase Enhances Seed Oil Content and Seed Weight
Plant Physiology,
June 1, 2001;
126(2):
861 - 874.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
X. Bao and J. Ohlrogge
Supply of Fatty Acid Is One Limiting Factor in the Accumulation of Triacylglycerol in Developing Embryos
Plant Physiology,
August 1, 1999;
120(4):
1057 - 1062.
[Abstract]
[Full Text]
|
 |
|
|
|