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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

Specificity of BnDGAT1 isozymes. Microsome aliquots from the yeast TAG mutant H1246 expressing the indicated BnDGAT1 isozyme were supplied with [14C]-palmitoyl-CoA or [14C]-oleoyl-CoA, along with either 1-palmitoyl-2-oleoyl-sn-glycerol (PO-DAG) or dioleoyl-sn-glycerol (OO-DAG). The DGAT1 activity was calculated based on radioactivity incorporated into TAG; results are means ±SD, n=3.
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Figure 5: Specificity of BnDGAT1 isozymes. Microsome aliquots from the yeast TAG mutant H1246 expressing the indicated BnDGAT1 isozyme were supplied with [14C]-palmitoyl-CoA or [14C]-oleoyl-CoA, along with either 1-palmitoyl-2-oleoyl-sn-glycerol (PO-DAG) or dioleoyl-sn-glycerol (OO-DAG). The DGAT1 activity was calculated based on radioactivity incorporated into TAG; results are means ±SD, n=3.

Mentions: Specificity of the DGAT enzymes for 16:0 and 18:1 were first examined by supplying the acyl-CoAs at 15 µM in separate reactions. All the BnDGAT1 isozymes were strongly specific for incorporation of palmitate (16:0) into PO-DAG, exhibiting both different levels of incorporation and different degrees of selective preference for 16:0 over 18:1. While interpretation of the absolute level of incorporation for each enzyme must be qualified by the vagaries of heterologous expression and in vitro analysis, the specificity of the enzymes for the substrates shows that, using PO-DAG, BnDGAT1-4 demonstrated the strongest preference for 16:0 over 18:1 incorporation, followed by BnDGAT1-1, BnDGAT1-3, and finally BnDGAT1-2 as the least specific. When using OO-DAG, BnDGAT1-4 again exhibited strong specificity for 16:0, but the other isozymes incorporated a lower ratio of 16:0 to 18:1 because 16:0 incorporation was lower than with PO-DAG cosubstrate (Fig. 5). In this heterologous expression system, the most active DGAT1 isoforms were BnDGAT1-2 and BnDGAT1-3.


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)

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

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getmorefigures.php?uid=PMC4588894&req=5

Figure 5: Specificity of BnDGAT1 isozymes. Microsome aliquots from the yeast TAG mutant H1246 expressing the indicated BnDGAT1 isozyme were supplied with [14C]-palmitoyl-CoA or [14C]-oleoyl-CoA, along with either 1-palmitoyl-2-oleoyl-sn-glycerol (PO-DAG) or dioleoyl-sn-glycerol (OO-DAG). The DGAT1 activity was calculated based on radioactivity incorporated into TAG; results are means ±SD, n=3.
Mentions: Specificity of the DGAT enzymes for 16:0 and 18:1 were first examined by supplying the acyl-CoAs at 15 µM in separate reactions. All the BnDGAT1 isozymes were strongly specific for incorporation of palmitate (16:0) into PO-DAG, exhibiting both different levels of incorporation and different degrees of selective preference for 16:0 over 18:1. While interpretation of the absolute level of incorporation for each enzyme must be qualified by the vagaries of heterologous expression and in vitro analysis, the specificity of the enzymes for the substrates shows that, using PO-DAG, BnDGAT1-4 demonstrated the strongest preference for 16:0 over 18:1 incorporation, followed by BnDGAT1-1, BnDGAT1-3, and finally BnDGAT1-2 as the least specific. When using OO-DAG, BnDGAT1-4 again exhibited strong specificity for 16:0, but the other isozymes incorporated a lower ratio of 16:0 to 18:1 because 16:0 incorporation was lower than with PO-DAG cosubstrate (Fig. 5). In this heterologous expression system, the most active DGAT1 isoforms were BnDGAT1-2 and BnDGAT1-3.

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