- Substrate specificity and regioselectivity of Δ12 and ω3 fatty acid desaturases from Saccharomyces kluyveri
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Δ12 and ω3 fatty acid desaturases are key enzymes in the synthesis of polyunsaturated fatty acids (PUFAs), which are important constituents of membrane glycerolipids and also precursors to signaling molecules in many organisms. In this study, we determined the substrate specificity and regioselectivity of the Δ12 and ω3 fatty acid desaturases from Saccharomyces kluyveri (Sk-FAD2 and Sk-FAD3). Based on heterologous expression in Saccharomyces cerevisiae, it was found that Sk-FAD2 converted C16-20 monounsaturated fatty acids to diunsaturated fatty acids by the introduction of a second double bond at the ν + 3 position, while Sk-FAD3 recognized the ω3 position of C18 and C20. Furthermore, fatty acid analysis of major phospholipids suggested that Sk-FAD2 and Sk-FAD3 have no strong substrate specificity toward the lipid polar head group or the sn-positions of fatty acyl groups in phospholipids.
- Oura, Takahiro,Kajiwara, Susumu
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experimental part
p. 3174 - 3179
(2009/04/07)
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- Chemical C2-elongation of polyunsaturated fatty acids
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Three fatty acids were synthesized from commercially available α-linolenic, stearidonic and eicosapentaenoic acids by C2-elongation using a four step preparative technique. The parent fatty acid methyl esters were reduced to alcohols with LiAlH4, converted to bromides by treatment with triphenylphosphine dibromide, coupled with a lithiated C2-elongation block - 2,4,4-trimethyl-2-oxazoline - to form the corresponding 2,2-dimethyloxazolines of C2-elongated fatty acids, and finally, converted to the target polyunsaturated fatty acids by acidic alcoholysis. Yields of more than 60% were achieved on a gram scale. The resulting 11Z,14Z,17Z-eicosatrienoic, 8Z,11Z,14Z,17Z-eicosatetraenoic and 7Z,10Z,13Z,16Z,19Z-docosapentaenoic acids were obtained as colorless oils with >98% purity and could be used for biochemical investigations without additional purification. The elongated fatty acids were free of byproducts that could result from Z-E isomerization or migration of double bonds.
- Kuklev, Dmitry V.,Smith, William L.
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p. 172 - 177
(2007/10/03)
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