title: High yield expression of functionally active human liver CYP2D6 in yeast cells.
abstract: In order to develop a model system for studying drug metabolism, we constructed recombinant yeast strains expressing human liver cytochromes P450. A high yield of cDNA-derived CYP2D6 was obtained, due to optimization of the initiation ATG codon context. The PCR-based site-mutagenesis method was used to introduce an AAA sequence immediately before the initiation codon resulting in increased translation of the GAL10-CYC1-derived mRNA. The use of a peptidase-deficient yeast strain also helped to increase the CYP2D6 content. A P450 content of 250 +/- 30 pmol per mg of microsomal protein was achieved. HPLC analysis confirmed that heterologously expressed CYP2D6 catalysed the oxidation of debrisoquine and dextromethorphan, two prototype substrates for CYP2D6. The Km for debrisoquine 4-hydroxylase was found to be 50 microM and Vmax 7.5 pmol mg-1 min-1. Dextromethorphan O-demethylase activity in CYP2D6-containing microsomes was characterized by Km 8.5 microM and Vmax 700 pmol mg-1 min-1. Biotransformation of debrisoquine and dextromethorphan was not detected in control microsomes. Yeast synthesizing CYP2D6 represents a useful in vitro system for studying xenobiotic metabolism.
authors.affiliation: Chemistry Faculty, Moscow State University, Russia.
authors.forename: E Y
authors.initials: EY
authors.lastname: Krynetski
authors.forename: V L
authors.initials: VL
authors.lastname: Drutsa
authors.forename: I E
authors.initials: IE
authors.lastname: Kovaleva
authors.forename: V N
authors.initials: VN
authors.lastname: Luzikov
mesh_terms: D001483:Base Sequence; D003001:Cloning, Molecular; D019389:Cytochrome P-450 CYP2D6; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D017931:DNA Primers; D018076:DNA, Complementary; D006801:Humans; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008861:Microsomes / Q000201:enzymology; D006899:Mixed Function Oxygenases / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D016133:Polymerase Chain Reaction; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D019389:Cytochrome P-450 CYP2D6