title: A vertebrate fatty acid desaturase with Delta 5 and Delta 6 activities.
abstract: Delta5 and Delta6 fatty acid desaturases are critical enzymes in the pathways for the biosynthesis of the polyunsaturated fatty acids arachidonic, eicosapentaenoic, and docosahexaenoic acids. They are encoded by distinct genes in mammals and Caenorhabditis elegans. This paper describes a cDNA isolated from zebrafish (Danio rerio) with high similarity to mammalian Delta6 desaturase genes. The 1,590-bp sequence specifies a protein that, in common with other fatty acid desaturases, contains an N-terminal cytochrome b(5) domain and three histidine boxes, believed to be involved in catalysis. When the zebrafish cDNA was expressed in Saccharomyces cerevisiae it conferred the ability to convert linoleic acid (18:2n-6) and alpha-linolenic acid (18:3n-3) to their corresponding Delta6 desaturated products, 18:3n-6 and 18:4n-3. However, in addition it conferred on the yeast the ability to convert di-homo-gamma-linoleic acid (20:3n-6) and eicosatetraenoic acid (20:4n-3) to arachidonic acid (20:4n-6) and eicosapentaenoic acid (20:5n-3), respectively, indicating that the zebrafish gene encodes an enzyme having both Delta5 and Delta6 desaturase activity. The zebrafish Delta5/Delta6 desaturase may represent a component of a prototypic vertebrate polyunsaturated fatty acids biosynthesis pathway.
authors.affiliation: Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, Scotland.
authors.forename: N
authors.initials: N
authors.lastname: Hastings
authors.forename: M
authors.initials: M
authors.lastname: Agaba
authors.forename: D R
authors.initials: DR
authors.lastname: Tocher
authors.forename: M J
authors.initials: MJ
authors.lastname: Leaver
authors.forename: J R
authors.initials: JR
authors.lastname: Dick
authors.forename: J R
authors.initials: JR
authors.lastname: Sargent
authors.forename: A J
authors.initials: AJ
authors.lastname: Teale
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D000090943:Delta-5 Fatty Acid Desaturase; D044943:Fatty Acid Desaturases / Q000235:genetics* / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D050602:Linoleoyl-CoA Desaturase; D008969:Molecular Sequence Data; D010802:Phylogeny; D012441:Saccharomyces cerevisiae / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D014170:Transformation, Genetic; D015027:Zebrafish / Q000235:genetics* / Q000378:metabolism*
chemical_list: D018076:DNA, Complementary; D000090943:Delta-5 Fatty Acid Desaturase; D005231:Fatty Acids, Unsaturated; D044943:Fatty Acid Desaturases; D050602:Linoleoyl-CoA Desaturase