Eicosapentaenoic acid: Difference between revisions

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=== Polyketide synthase pathway ===

[[File:LA--) EPA.pdf|thumb|upright=1.5|α-linolenic acid to EPA via PKS]]

Marine bacteria and the microalgae ''[[Schizochytrium]]'' use an anerobic [[polyketide synthase]] (PKS) pathway to synthesize DHA.~~<ref name=Qiu/>~~ The PKS pathway includes six enzymes namely, 3-ketoacyl synthase (KS), 2 ketoacyl-ACP-reductase(KR), dehydrase (DH), enoyl reductase (ER), dehydratase/2-trans 3-cos isomerase (DH/2,3I), dehydratase/2-trans, and 2-cis isomerase(DH/2,2I). The biosynthesis of EPA varies in marine species, but most of the marine species' ability to convert C18 [[PUFA]] to LC-PUFA is dependent on the fatty acyl desaturase and elongase enzymes. The molecule basis of the enzymes will dictate where the double bond is formed on the resulting molecule.

Marine bacteria and the microalgae ''[[Schizochytrium]]'' use an anerobic [[polyketide synthase]] (PKS) pathway to synthesize DHA. The PKS pathway includes six enzymes namely, 3-ketoacyl synthase (KS), 2 ketoacyl-ACP-reductase(KR), dehydrase (DH), enoyl reductase (ER), dehydratase/2-trans 3-cos isomerase (DH/2,3I), dehydratase/2-trans, and 2-cis isomerase(DH/2,2I). The biosynthesis of EPA varies in marine species, but most of the marine species' ability to convert C18 [[PUFA]] to LC-PUFA is dependent on the fatty acyl desaturase and elongase enzymes. The molecule basis of the enzymes will dictate where the double bond is formed on the resulting molecule.

The proposed polyketide synthesis pathway of EPA in ''Shewanella'' (a marine bacterium) is a repetitive reaction of reduction, dehydration, and condensation that uses acetyl coA and malonyl coA as building blocks. The mechanism of α-linolenic acid to EPA involves the condensation of malonyl-CoA to the pre-existing α-linolenic acid by KS. The resulting structure is converted by NADPH dependent reductase, KR, to form an intermediate that is dehydrated by the DH enzyme. The final step is the NADPH-dependent reduction of a double bond in trans-2-enoly-ACP via ER enzyme activity. The process is repeated to form EPA.

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 === Polyketide synthase pathway ===
 [[File:LA--) EPA.pdf|thumb|upright=1.5|α-linolenic acid to EPA via PKS]]
-Marine bacteria and the microalgae ''[[Schizochytrium]]'' use an anerobic [[polyketide synthase]] (PKS) pathway to synthesize DHA.<ref name=Qiu/> The PKS pathway includes six enzymes namely, 3-ketoacyl synthase (KS), 2 ketoacyl-ACP-reductase(KR), dehydrase (DH), enoyl reductase (ER), dehydratase/2-trans 3-cos isomerase (DH/2,3I), dehydratase/2-trans, and 2-cis isomerase(DH/2,2I). The biosynthesis of EPA varies in marine species, but most of the marine species' ability to convert C18 [[PUFA]] to LC-PUFA is dependent on the fatty acyl desaturase and elongase enzymes. The molecule basis of the enzymes will dictate where the double bond is formed on the resulting molecule.
+Marine bacteria and the microalgae ''[[Schizochytrium]]'' use an anerobic [[polyketide synthase]] (PKS) pathway to synthesize DHA. The PKS pathway includes six enzymes namely, 3-ketoacyl synthase (KS), 2 ketoacyl-ACP-reductase(KR), dehydrase (DH), enoyl reductase (ER), dehydratase/2-trans 3-cos isomerase (DH/2,3I), dehydratase/2-trans, and 2-cis isomerase(DH/2,2I). The biosynthesis of EPA varies in marine species, but most of the marine species' ability to convert C18 [[PUFA]] to LC-PUFA is dependent on the fatty acyl desaturase and elongase enzymes. The molecule basis of the enzymes will dictate where the double bond is formed on the resulting molecule.
 The proposed polyketide synthesis pathway of EPA in ''Shewanella'' (a marine bacterium) is a repetitive reaction of reduction, dehydration, and condensation that uses acetyl coA and malonyl coA as building blocks. The mechanism of α-linolenic acid to EPA involves the condensation of malonyl-CoA to the pre-existing α-linolenic acid by KS. The resulting structure is converted by NADPH dependent reductase, KR, to form an intermediate that is dehydrated by the DH enzyme. The final step is the NADPH-dependent reduction of a double bond in trans-2-enoly-ACP via ER enzyme activity. The process is repeated to form EPA.