ABSTRACT
Selected filamentous fungi--98 strains of 31 genera--were screened for the ability to catalyze 11beta-hydroxylation of 6alpha-fluoro-16alpha-methyl-deoxycorticosterone 21-acetate (FM-DCA). It was established that representatives of the genera Gongronella, Scopulariopsis, Epicoccum, and Curvularia have the ability to activate 11beta-hydroxylase steroids. The strains of Curvularia lunata VKM F-644 and Gongronella butleri VKM F-1033 expressed maximal activity and formed 6lpha-fluoro-16alpha-methyl-corticosterone as a major bioconversion product from FM-DCA. The structures of the major products and intermediates of the bioconversion were confirmed by TLC, H PLC, MS and 1H NMR analyses. Different pathways of 6alpha-fluoro-16alpha-methyl-corticosterone formation by C. lunata and G. butleri strains were proposed based on intermediate identification. The constitutive character and membrane-binding localization were evidence of a 11beta-hydroxylating system in G. butleri, while an inducible character and microsomal localization was confirmed for 11beta-hydroxylase of C. lunata. Under optimized conditions, the molar yield of 6alpha-fluoro-16alpha-methyl-corticosterone reached 65% at a FM-DCA substrate loading of 6 g/L.
Subject(s)
Desoxycorticosterone/analogs & derivatives , Mitosporic Fungi/metabolism , Ascomycota/metabolism , Chromatography, High Pressure Liquid , Desoxycorticosterone/metabolism , Enzymes/metabolism , Hydroxylation , Magnetic Resonance Spectroscopy , Molecular StructureABSTRACT
The strain of Mycobacterium sp. VKM Ac-1817D forms 9alpha-hydroxy-androst-4-ene-3,17-dione (9-OH-AD) as a major product from sitosterol. The formation of 9-OH-AD was accompanied with its partial destruction due to residual steroid-1-dehydrogenase (St1DH) activity. The activity was found to be induced by androst-4-ene-3,17-dione (AD), while other intermediates of sitosterol oxidation did not influence 1(2)-dehydrogenation. The enzyme is located mainly in the cytosolic fraction. The cytosolic St1DH (dimer, M (r) approximately 58 kDa) was partially purified by ammonium sulfate fractionation, ion-exchange chromatography on DEAE-Sepharose and Phenyl-Sepharose, and gel filtration on Bio-Gel A-0.5M. It expressed the St1DH activity toward both AD and 9-OH-AD.
Subject(s)
Androstenedione/analogs & derivatives , Mycobacterium/enzymology , Oxidoreductases/isolation & purification , Oxidoreductases/metabolism , Sitosterols/metabolism , Ammonium Sulfate , Androstenedione/biosynthesis , Chemical Fractionation , Chromatography, Gel , Chromatography, Ion Exchange , Cytosol/chemistry , Enzyme Induction , Models, Biological , Molecular Structure , Molecular Weight , Mycobacterium/geneticsABSTRACT
Biotransformation of 1-benzoylindole (BI) by the strains Aspergillus flavus VKM F-1024 and Aspergillus oryzae VKM F-44 was studied. The major metabolites isolated were identified as 4-hydroxyindole (4-HI), 5-hydroxyindole (5-HI), 4-hydroxy- -benzoylindole, 4-hydroxy-1-(4'-hydroxy)-benzoylindole and indole. The structure of the metabolites was determined by mass spectrometry and proton nuclear magnetic resonance spectroscopy. The pathways of BI metabolism via initial monohydroxylation at C-4 and C-5 followed by cleavage of the benzoyl substituent to yield 4-HI and 5-HI were proposed. Indole was formed as a by-product, and its role as a potent inhibitor of BI hydroxylation at C-4 and C-5 is discussed.
