title: CYP2U1, a novel human thymus- and brain-specific cytochrome P450, catalyzes omega- and (omega-1)-hydroxylation of fatty acids.
abstract: Long chain fatty acids have recently emerged as critical signaling molecules in neuronal, cardiovascular, and renal processes, yet little is presently known about the precise mechanisms controlling their tissue distribution and bioactivation. We have identified a novel cytochrome P450, CYP2U1, which may play an important role in modulating the arachidonic acid signaling pathway. Northern blot and real-time PCR analysis demonstrated that CYP2U1 transcripts were most abundant in the thymus and the brain (cerebellum), indicating a specific physiological role for CYP2U1 in these tissues. Recombinant human CYP2U1 protein, expressed in baculovirus-infected Sf9 insect cells, was found to metabolize arachidonic acid exclusively to two region-specific products as determined by liquid chromatography-mass spectrometry. These metabolites were identified as 19- and 20-hydroxy-modified arachidonic acids by liquid chromatography-tandem mass spectrometry analysis. In addition to omega/omega-1 hydroxylation of arachidonic acid, CYP2U1 protein also catalyzed the hydroxylation of structurally related long chain fatty acid (docosahexaenoic acid) but not fatty acids such as lauric acid or linoleic acid. This is the first report of the cloning and functional expression of a new human member of P450 family 2, CYP2U1, which metabolizes long chain fatty acids. Based on the ability of CYP2U1 to generate bioactive eicosanoid derivatives, we postulate that CYP2U1 plays an important physiological role in fatty acid signaling processes in both cerebellum and thymus.
authors.affiliation: Cytochroma, Inc, Markham, Ontario L3R 8E4, Canada.
authors.forename: Samuel S
authors.initials: SS
authors.lastname: Chuang
authors.forename: Christian
authors.initials: C
authors.lastname: Helvig
authors.forename: Mohammed
authors.initials: M
authors.lastname: Taimi
authors.forename: Heather A
authors.initials: HA
authors.lastname: Ramshaw
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Collop
authors.forename: Ma'an
authors.initials: M
authors.lastname: Amad
authors.forename: Jay A
authors.initials: JA
authors.lastname: White
authors.forename: Martin
authors.initials: M
authors.lastname: Petkovich
authors.forename: Glenville
authors.initials: G
authors.lastname: Jones
authors.forename: Bozena
authors.initials: B
authors.lastname: Korczak
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism; D016367:Baculoviridae; D001483:Base Sequence; D015153:Blotting, Western; D001921:Brain / Q000201:enzymology*; D002384:Catalysis; D002460:Cell Line; D002853:Chromatography, Liquid; D042926:Cytochrome P-450 CYP4A / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis* / Q000737:chemistry*; D000072467:Cytochrome P450 Family 2; D018076:DNA, Complementary / Q000378:metabolism; D020224:Expressed Sequence Tags; D005227:Fatty Acids / Q000737:chemistry*; D006801:Humans; D006893:Hydroxyeicosatetraenoic Acids / Q000737:chemistry; D015151:Immunoblotting; D007313:Insecta; D013058:Mass Spectrometry; D008861:Microsomes / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000096:biosynthesis* / Q000737:chemistry*; D008969:Molecular Sequence Data; D005810:Multigene Family; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D015398:Signal Transduction; D013379:Substrate Specificity; D013950:Thymus Gland / Q000201:enzymology* / Q000378:metabolism; D013997:Time Factors; D014018:Tissue Distribution; D017962:alpha-Linolenic Acid / Q000737:chemistry
chemical_list: D001095:Arachidonic Acids; D018076:DNA, Complementary; D005227:Fatty Acids; D006893:Hydroxyeicosatetraenoic Acids; D012333:RNA, Messenger; D011994:Recombinant Proteins; D017962:alpha-Linolenic Acid; C055986:19-hydroxy-5,8,11,14-eicosatetraenoic acid; C055987:20-hydroxy-5,8,11,14-eicosatetraenoic acid; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; C484320:CYP2U1 protein, human; D000072467:Cytochrome P450 Family 2; D042926:Cytochrome P-450 CYP4A