title: Regioselective hydroxylation of isoflavones by Streptomyces avermitilis MA-4680.
abstract: Screening of bacterial whole cells was performed for regioselective hydroxylation of daidzein and genistein. Among the strains examined, Streptomyces avermitilis MA-4680 showed high ortho-dihydroxylation activity to produce 3',4',7-trihydroxyisoflavone and 3',4',5,7-tetrahydroxyisoflavone from daidzein (4',7-dihydroxyisoflavone) and genistein (4',5,7-trihydroxyisoflavone), respectively. Using 100 mg cells (wet wt.) and 1% (v/v) Triton X100 in 1 ml of total reaction volume, where 100 microl of the substrate solution (0.5 mM in 10% (v/v) mixed solvent of DMSO:MeOH = 3:7) was added to 900 microl of potassium phosphate buffer (100 mM, pH 7.2), a 16% molar conversion yield of 3',4',7-trihydroxyisoflavone was obtained from 0.5 mM daidzein after 24 h of reaction time at 28 degrees C and 200 rpm. Ketoconazole significantly (ca. 90%) inhibited the ortho-hydroxylation activity of daidzein, suggesting that cytochrome P450 enzymes putatively play roles in regiospecific daidzein hydroxylation. The analysis of the reaction products was determined by gas chromatography/mass spectrometry (GC/MS) and (1)H NMR.
authors: School of Chemical and Biological Engineering, Institute of Molecular Biology and Genetics, Institute of Bioengineering, Seoul National University, Seoul, South Korea.
authors: Changhyun
authors: C
authors: Roh
authors: Su-Hyun
authors: SH
authors: Seo
authors: Kwon-Young
authors: KY
authors: Choi
authors: Minho
authors: M
authors: Cha
authors: Bishnu Prasad
authors: BP
authors: Pandey
authors: June-Hyung
authors: JH
authors: Kim
authors: Jun-Seong
authors: JS
authors: Park
authors: Duck Hee
authors: DH
authors: Kim
authors: Ih Seop
authors: IS
authors: Chang
authors: Byung-Gee
authors: BG
authors: Kim
mesh_terms: D001711:Biotransformation; D065607:Cytochrome P-450 Enzyme Inhibitors; D003902:Detergents / Q000737:chemistry; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008401:Gas Chromatography-Mass Spectrometry; D006900:Hydroxylation; D007529:Isoflavones / Q000378:metabolism* / Q000493:pharmacokinetics; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D013302:Streptomyces / Q000378:metabolism*
chemical_list: D065607:Cytochrome P-450 Enzyme Inhibitors; D003902:Detergents; D004791:Enzyme Inhibitors; D007529:Isoflavones