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Type 1 diacylglycerol acyltransferases of Brassica napus preferentially incorporate oleic acid into triacylglycerol.

Aznar-Moreno J, Denolf P, Van Audenhove K, De Bodt S, Engelen S, Fahy D, Wallis JG, Browse J - J. Exp. Bot. (2015)

Bottom Line: Thorough understanding of the enzymology of oil accumulation is critical to the goal of modifying oilseeds for improved vegetable oil production.This strong sensitivity of the BnDGAT1 isozymes to the relative concentrations of acyl-CoA substrates substantially explains the observed fatty acid composition of B. napus seed oil.Understanding these enzymes that are critical for triacylglycerol synthesis will facilitate genetic and biotechnological manipulations to improve this oilseed crop.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA.

No MeSH data available.


Related in: MedlinePlus

Selectivity of BnDGAT1 isozymes with equimolar acyl-CoA substrates. Microsome aliquots from the yeast TAG mutant H1246 expressing the indicated BnDGAT1 isozyme were supplied with [14C]-palmitoyl-CoA and simultaneously with [3H]-oleoyl-CoA, along with either 1-palmitoyl-2-oleoyl-sn-glycerol (PO-DAG) or dioleoyl-sn-glycerol (OO-DAG). 15 µM of each acyl-CoA were supplied. The DGAT1 activity was calculated based on radioactivity incorporated into TAG; results are means ±SD, n=3.
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Figure 6: Selectivity of BnDGAT1 isozymes with equimolar acyl-CoA substrates. Microsome aliquots from the yeast TAG mutant H1246 expressing the indicated BnDGAT1 isozyme were supplied with [14C]-palmitoyl-CoA and simultaneously with [3H]-oleoyl-CoA, along with either 1-palmitoyl-2-oleoyl-sn-glycerol (PO-DAG) or dioleoyl-sn-glycerol (OO-DAG). 15 µM of each acyl-CoA were supplied. The DGAT1 activity was calculated based on radioactivity incorporated into TAG; results are means ±SD, n=3.

Mentions: Next, selectivity of the four isozymes for the two principal acyl-CoA substrates were examined by conducting assays including both 16:0-CoA and 18:1-CoA together in the assays, as [14C]-labelled palmitoyl-CoA and [3H]-labelled oleoyl-CoA. When activities in the presence of equimolar mixtures of the substrates were compared (Fig. 6), the results indicated that 16:0-CoA was again the preferred substrate; BnDGAT1-3 showed the highest selectivity for incorporating 16:0 with either PO-DAG or OO-DAG substrate, followed by BnDGAT1-1, BnDGAT1-2, and finally BnDGAT1-4. BnDGAT1-4 was notably less active in incorporating 16:0 into TAG when the 18:1 substrate is also present, losing ∼40% of its 16:0-incorporation activity. The four enzymes all incorporated more oleoyl fatty acid than when assayed separately, but the changes were quite modest (Fig. 6).


Type 1 diacylglycerol acyltransferases of Brassica napus preferentially incorporate oleic acid into triacylglycerol.

Aznar-Moreno J, Denolf P, Van Audenhove K, De Bodt S, Engelen S, Fahy D, Wallis JG, Browse J - J. Exp. Bot. (2015)

Selectivity of BnDGAT1 isozymes with equimolar acyl-CoA substrates. Microsome aliquots from the yeast TAG mutant H1246 expressing the indicated BnDGAT1 isozyme were supplied with [14C]-palmitoyl-CoA and simultaneously with [3H]-oleoyl-CoA, along with either 1-palmitoyl-2-oleoyl-sn-glycerol (PO-DAG) or dioleoyl-sn-glycerol (OO-DAG). 15 µM of each acyl-CoA were supplied. The DGAT1 activity was calculated based on radioactivity incorporated into TAG; results are means ±SD, n=3.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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Figure 6: Selectivity of BnDGAT1 isozymes with equimolar acyl-CoA substrates. Microsome aliquots from the yeast TAG mutant H1246 expressing the indicated BnDGAT1 isozyme were supplied with [14C]-palmitoyl-CoA and simultaneously with [3H]-oleoyl-CoA, along with either 1-palmitoyl-2-oleoyl-sn-glycerol (PO-DAG) or dioleoyl-sn-glycerol (OO-DAG). 15 µM of each acyl-CoA were supplied. The DGAT1 activity was calculated based on radioactivity incorporated into TAG; results are means ±SD, n=3.
Mentions: Next, selectivity of the four isozymes for the two principal acyl-CoA substrates were examined by conducting assays including both 16:0-CoA and 18:1-CoA together in the assays, as [14C]-labelled palmitoyl-CoA and [3H]-labelled oleoyl-CoA. When activities in the presence of equimolar mixtures of the substrates were compared (Fig. 6), the results indicated that 16:0-CoA was again the preferred substrate; BnDGAT1-3 showed the highest selectivity for incorporating 16:0 with either PO-DAG or OO-DAG substrate, followed by BnDGAT1-1, BnDGAT1-2, and finally BnDGAT1-4. BnDGAT1-4 was notably less active in incorporating 16:0 into TAG when the 18:1 substrate is also present, losing ∼40% of its 16:0-incorporation activity. The four enzymes all incorporated more oleoyl fatty acid than when assayed separately, but the changes were quite modest (Fig. 6).

Bottom Line: Thorough understanding of the enzymology of oil accumulation is critical to the goal of modifying oilseeds for improved vegetable oil production.This strong sensitivity of the BnDGAT1 isozymes to the relative concentrations of acyl-CoA substrates substantially explains the observed fatty acid composition of B. napus seed oil.Understanding these enzymes that are critical for triacylglycerol synthesis will facilitate genetic and biotechnological manipulations to improve this oilseed crop.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA.

No MeSH data available.


Related in: MedlinePlus