Human CYP1A1 variants lead to differential eicosapentaenoic acid metabolite patterns

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Item Type:	Article
Title:	Human CYP1A1 variants lead to differential eicosapentaenoic acid metabolite patterns
Creators Name:	Schwarz, D., Kisselev, P., Chernogolov, A., Schunck, W.H. and Roots, I.
Abstract:	To answer the question whether the most common allelic variants of human CYP1A1, namely CYP1A1.1 (wild type), CYP1A1.2 (Ile462Val), and CYP1A1.4 (Thr461Asn), differ in their catalytic activity towards eicosapentaenoic acid (EPA), in vitro enzymatic assays were performed in reconstituted CYP1A1 systems. All CYP1A1 variants catalyzed EPA epoxygenation and hydroxylation to 17(R),18(S)-epoxyeicosatetraenoic acid (17(R),18(S)-EETeTr) and 19-OH-EPA, yet with varying catalytic efficiency and distinct regiospecificity. CYP1A1.1 and CYP1A1.4 formed 17(R),18(S)-EETeTr as main product (Km = 53 and 50 μM; Vmax = 0.60 and 0.50 pmol/min/pmol; Vmax/K m = 0.11 and 0.10 μM-1 min-1, respectively), followed by 19-OH-EPA (Km = 76 and 93 μM; Vmax = 0.37 and 0.37 pmol/min/pmol; Vmax/Km = 0.005 and 0.004 μM-1 min-1, respectively). The variant CYP1A1.2 produced almost equal amounts of both metabolites, but its catalytic efficiency for hydroxylation was five times higher (Km = 66 μM; V max = 1.7 pmol/min/pmol; Vmax/Km = 0.026 μM-1 min-1) and that for epoxygenation was twice higher (Km = 66 μM; Vmax = 1.5 pmol/min/pmol; V max/Km = 0.023 μM-1 min-1) than those of the wild-type enzyme. Thus, the Ile462Val polymorphism in human CYP1A1 affects EPA metabolism and may contribute to interindividual variance in the local production of physiologically active fatty acid metabolites in the cardiovascular system and other extrahepatic tissues, where CYP1A1 is expressed or induced by polycyclic aromatic hydrocarbons and other xenobiotics.
Keywords:	CYP1A1, Cytochrome P450 1A1, Eicosapentaenoic Acid, Epoxyeicosatetraenoic Acid, Genetic Polymorphism, Hydroxyeicosapentaenoic Acid, Pharmacogenetics, Polyunsaturated Fatty Acid, Vasoactive Metabolite
Source:	Biochemical and Biophysical Research Communications
ISSN:	0006-291X
Publisher:	Academic Press
Volume:	336
Number:	3
Page Range:	779-783
Date:	29 August 2005
Official Publication:	https://doi.org/10.1016/j.bbrc.2005.08.172
PubMed:	View item in PubMed

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