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Delta-8 desaturation activity varies among fatty acyl desaturases of teleost fish: high activity in delta-6 desaturases of marine species.

Abstract

The benefits of dietary fish and fish oil are derived from n-3 long-chain polyunsaturated fatty acids (LC-PUFA) that have beneficial effects in a range of human diseases and pathologies such as cardiovascular and other inflammatory disorders, neural development and neurological pathologies. The precursor of n-3 LC-PUFA, 18:3n-3 does not have the same beneficial effects prompting interest in the pathways of endogenous synthesis of LC-PUFA in vertebrates. The LC-PUFA biosynthesis pathway classically involves Δ6 and Δ5 fatty acyl desaturases (Fad), but it was recently shown that Δ6 Fad in mammals also displayed Δ8 activity demonstrating a possible alternative "Δ8-pathway" for the synthesis of LC-PUFA. Our primary hypothesis was that Δ8 desaturase activity would be a common feature of vertebrate Δ6 Fads, and so the aim of the present study was to determine the ability of teleostei Fads for Δ8 desaturation activity. To this end, cDNAs for Fads from a range of freshwater, diadromous and marine teleost fish species were assayed for Δ8 activity in the heterologous yeast expression system. In summary, the present study has demonstrated that Δ8 desaturation activity was also a characteristic of fish orthologs, although the activity varied notably between freshwater/diadromous and marine fish species, with the latter possessing Fads2-like proteins with Δ8 activity far higher than mammalian FADS2. The data showed that, generally, the fish Fad are technically υ-3 desaturases, with new double bonds introduced 3C beyond a pre-existing double bond. However, the ability of zebrafish and rabbitfish Fads, previously characterised as Δ6/Δ5 bifunctional desaturases, to introduce non-methylene interrupted double bonds in 20:3n-3 and 20:2n-6 suggested that a novel combination of regioselectivity modes operates within these enzymes.

Authors+Show Affiliations

Institute of Aquaculture, School of Natural Sciences, University of Stirling, Scotland, UK. oscarmonroig@yahoo.esNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

21571087

Citation

Monroig, Oscar, et al. "Delta-8 Desaturation Activity Varies Among Fatty Acyl Desaturases of Teleost Fish: High Activity in Delta-6 Desaturases of Marine Species." Comparative Biochemistry and Physiology. Part B, Biochemistry & Molecular Biology, vol. 159, no. 4, 2011, pp. 206-13.
Monroig O, Li Y, Tocher DR. Delta-8 desaturation activity varies among fatty acyl desaturases of teleost fish: high activity in delta-6 desaturases of marine species. Comp Biochem Physiol B, Biochem Mol Biol. 2011;159(4):206-13.
Monroig, O., Li, Y., & Tocher, D. R. (2011). Delta-8 desaturation activity varies among fatty acyl desaturases of teleost fish: high activity in delta-6 desaturases of marine species. Comparative Biochemistry and Physiology. Part B, Biochemistry & Molecular Biology, 159(4), pp. 206-13. doi:10.1016/j.cbpb.2011.04.007.
Monroig O, Li Y, Tocher DR. Delta-8 Desaturation Activity Varies Among Fatty Acyl Desaturases of Teleost Fish: High Activity in Delta-6 Desaturases of Marine Species. Comp Biochem Physiol B, Biochem Mol Biol. 2011;159(4):206-13. PubMed PMID: 21571087.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Delta-8 desaturation activity varies among fatty acyl desaturases of teleost fish: high activity in delta-6 desaturases of marine species. AU - Monroig,Oscar, AU - Li,Yuanyou, AU - Tocher,Douglas R, Y1 - 2011/05/06/ PY - 2011/03/16/received PY - 2011/04/25/revised PY - 2011/04/25/accepted PY - 2011/5/17/entrez PY - 2011/5/17/pubmed PY - 2012/2/3/medline SP - 206 EP - 13 JF - Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology JO - Comp. Biochem. Physiol. B, Biochem. Mol. Biol. VL - 159 IS - 4 N2 - The benefits of dietary fish and fish oil are derived from n-3 long-chain polyunsaturated fatty acids (LC-PUFA) that have beneficial effects in a range of human diseases and pathologies such as cardiovascular and other inflammatory disorders, neural development and neurological pathologies. The precursor of n-3 LC-PUFA, 18:3n-3 does not have the same beneficial effects prompting interest in the pathways of endogenous synthesis of LC-PUFA in vertebrates. The LC-PUFA biosynthesis pathway classically involves Δ6 and Δ5 fatty acyl desaturases (Fad), but it was recently shown that Δ6 Fad in mammals also displayed Δ8 activity demonstrating a possible alternative "Δ8-pathway" for the synthesis of LC-PUFA. Our primary hypothesis was that Δ8 desaturase activity would be a common feature of vertebrate Δ6 Fads, and so the aim of the present study was to determine the ability of teleostei Fads for Δ8 desaturation activity. To this end, cDNAs for Fads from a range of freshwater, diadromous and marine teleost fish species were assayed for Δ8 activity in the heterologous yeast expression system. In summary, the present study has demonstrated that Δ8 desaturation activity was also a characteristic of fish orthologs, although the activity varied notably between freshwater/diadromous and marine fish species, with the latter possessing Fads2-like proteins with Δ8 activity far higher than mammalian FADS2. The data showed that, generally, the fish Fad are technically υ-3 desaturases, with new double bonds introduced 3C beyond a pre-existing double bond. However, the ability of zebrafish and rabbitfish Fads, previously characterised as Δ6/Δ5 bifunctional desaturases, to introduce non-methylene interrupted double bonds in 20:3n-3 and 20:2n-6 suggested that a novel combination of regioselectivity modes operates within these enzymes. SN - 1879-1107 UR - https://www.unboundmedicine.com/medline/citation/21571087/Delta_8_desaturation_activity_varies_among_fatty_acyl_desaturases_of_teleost_fish:_high_activity_in_delta_6_desaturases_of_marine_species_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1096-4959(11)00084-4 DB - PRIME DP - Unbound Medicine ER -