- The generation of a steroid library using filamentous fungi immobilized in calcium alginate Dedicated to the memory of Professor Sir John W. Cornforth, University of Sussex (1917-2013).
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Four fungi, namely, Rhizopus oryzae ATCC 11145, Mucor plumbeus ATCC 4740, Cunninghamella echinulata var. elegans ATCC 8688a, and Whetzelinia sclerotiorum ATCC 18687, were subjected to entrapment in calcium alginate, and the beads derived were used in the biotransformation of the steroids 3β,17β-dihydroxyandrost-5-ene (1) and 17β-hydroxyandrost-4-en-3-one (2). Incubations performed utilized beads from two different encapsulated fungi to explore their potential for the production of metabolites other than those derived from the individual fungi. The investigation showed that steroids from both single and crossover transformations were typically produced, some of which were hitherto unreported. The results indicated that this general technique can be exploited for the production of small libraries of compounds.
- Peart, Patrice C.,Reynolds, William F.,Reese, Paul B.
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- Novel metabolites of dehydroepiandrosterone and progesterone obtained in Didymosphearia igniaria KCH 6670 culture
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Dehydroepiandrosterone (DHEA) (10) and its five derivatives: testosterone (1), androstenedione (2), 17α-methyltestosterone (6), progesterone (13) and pregnenolone (14) were subjected to microbial transformation by the filamentous fungus Didymosphaeria igniaria KCH 6670. The predominant metabolism of the incubated 5-ene steroids (10 and 14) occurred through 3β-hydroxy-steroid dehydrogenase/5,4-en isomerase pathways resulting in the generation of a 4-en-3-oxo system on ring-A. The transformations of C 19 steroids (1, 2, and 10) included a hydroxylation at 7α position, ketone-alcohol interconversion at C-17 and reduction of the double bond at C-4 and 3-keto group to the 3β-alcohol with 5α- stereochemistry at A/B ring. D. igniaria also carried out 6(7)-dehydrogenation and 6,7β-epoxidation during transformation of DHEA. Under these conditions transformation of DHEA (10) gave four products: 7α-hydroxyandrost-4-en-3, 17-dione (4), 17β-hydroxyandrost-4,6-dien-3-one (11), 17β- hydroxyandrost-6β-epoxy-4-en-3-one (12) and 3β,17β-dihydroxy- 5α-androstane (5). The compounds 11 and 12 are identified as DHEA metabolites for the first time. The transformation of C21 steroids (13 and 14) led to the mixture of mono- (mainly 11α- and 15β-) and dihydroxy- (7α,15β-; 14α,15β-; 11α,15β-; 11α,14α-) products. 7α,15β-Dihydroxypregnan-4-en-3,20- dione (18) and 14α,15β-dihydroxypregnan-4-en-3,20-dione (19) were found to be new compounds. The main product of transformation of 17α-methyltestosterone (6) was 12β-hydroxy-17α- methyltestosterone (7). The results of these transformations demonstrate the dependence of hydroxylation position on the structure of steroid nucleus.
- Janeczko, Tomasz,Swizdor, Alina,Dmochowska-Gladysz, Jadwiga,Bialonska, Agata,Ciunik, Zbigniew,Kostrzewa-Suslow, Edyta
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experimental part
p. 24 - 31
(2012/10/08)
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- Biotransformation of methyltestosterone by the filamentous fungus Mucor racemosus
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Fungi have proved to be powerful biocatalysts in steroid biotransformations. In the present study, the soil isolate filamentous fungus Mucor racemosus was applied for bioconversion of methyltestosterone (1), an anabolic steroid, in a five-day fermentation. Microbial metabolites were purified chromatographically and identified on the basis of their spectral data as 7α-hydroxymethyltestosterone (2), 15α-hydroxymethyltestosterone (3), and 12,15α-dihydroxymethyltestosterone (4). Observed modifications were hydroxylations at C-7α, C-12, and 15α-positions. Best fermentation condition for production of hydroxylated derivatives was found to be 25°C at 150 rpm for 5 days with a substrate concentration of 1 mg/mL.
- Torshabi,Badiee,Faramarzi,Rastegar,Forootanfar,Mohit
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experimental part
p. 59 - 63
(2011/07/30)
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- Kinetic study of HCG induced decrease of microsomal 7α-hydroxylase activity in rat testes
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Microsomes from rat testes were incubated with varying concentrations of 14C labelled testosterone and androstenedione. The production of 7α-hydroxytestosterone and 7α-hydroxyandrostenedione was followed; K(m) and V(m) values were calculated from Lineweaver-Burk curves. A sustained treatment of rats with HCG resulted in a considerable decrease of the maximal 7α-hydroxylation rate (V(m)) whereas the K(m) value was not changed. V(m) of microsomes from normal rats, when incubated with microsomes from HCG-treated animals, was also decreased substantially. It is concluded that HCG-induced depression of 7α-hydroxylation capacity of testicular microsomes is at least in part due to non-competitive inhibition of the enzyme.
- Eechaute,Lacroix,Leusen
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p. 647 - 660
(2007/10/02)
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