- Microbial transformation of epiandrosterone by Aspergillus sydowii
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Incubation of epiandrosterone with Aspergillus sydowii MRC 200653 afforded ten metabolites. The fungal dehydrogenation of epiandrosterone is reported for the first time. The formation of the major metabolite, 6?-hydroxyandrost-4-ene-3,17-dione, involved first dehydrogenation to give a 4-ene and then hydroxylation at C-6?. Small amounts of the substrate were hydroxylated at C-1α, C-7α, C-7β and C-11α.
- Yildirim, Kudret,Kuru, Ali
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p. 718 - 721
(2016/12/30)
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- Old yellow enzyme-catalyzed dehydrogenation of saturated ketones
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Enzymes from extremophiles have always been of great interest for biotechnology because of their ruggedness against various stress factors. We have isolated, cloned, heterologously expressed and characterized a thermostable old yellow enzyme (OYE) from Geobacillus kaustophilus. In addition to the expected 'enone' reduction, GkOYE also catalyzes the reverse reaction, i.e., the desaturation of C-C bonds adjacent to a carbonyl to give the corresponding α,β-unsaturated ketone. The reaction proceeds at the expense of molecular oxygen without the need for a nicotinamide cofactor and represents an environmentally benign alternative to known chemical dehydrogenation methods.
- Schittmayer, Matthias,Glieder, Anton,Uhl, Michael K.,Winkler, Andreas,Zach, Simone,Schrittwieser, Joerg H.,Kroutil, Wolfgang,MacHeroux, Peter,Gruber, Karl,Kambourakis, Spiros,Rozzell, J. David,Winkler, Margit
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experimental part
p. 268 - 274
(2011/04/22)
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- Endogenous boldenone-formation in cattle: Alternative invertebrate organisms to elucidate the enzymatic pathway and the potential role of edible fungi on cattle's feed
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Although β-boldenone (bBol) used to be a marker of illegal steroid administration in calves, its endogenous formation has recently been demonstrated in these vertebrates. However, research on the pathway leading to bBol remains scarce. This study shows the usefulness of in vivo invertebrate models as alternatives to vertebrate animal experiments, using Neomysis integer and Lucilia sericata. In accordance with vertebrates, androstenedione (AED) was the main metabolite of β-testosterone (bT) produced by these invertebrates, and bBol was also frequently detected. Moreover, in vitro experiments using feed-borne fungi and microsomes were useful to perform the pathway from bT to bBol. Even the conversion of phytosterols into steroids was shown in vitro. Both in vivo and in vitro, the conversion of bT into bBol could be demonstrated in this study. Metabolism of phytosterols by feed-borne fungi may be of particular importance to explain the endogenous bBol-formation by cattle. To the best of our knowledge, it is the first time the latter pathway is described in literature.
- Verheyden,Noppe,Zorn,Van Immerseel,Bussche, J. Vanden,Wille,Bekaert,Janssen,De Brabander,Vanhaecke
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experimental part
p. 161 - 170
(2011/03/19)
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- A practical Δ1-dehydrogenation of Δ4-3-keto-steroids with DDQ in the presence of TBDMSCl at room temperature
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A mild and efficient Δ1-dehydrogenation of Δ4-3-keto-steroids with DDQ in the presence of tertbutyldimethylchlorosilane at room temperature was developed.
- Chen, Kaixiong,Liu, Chang,Deng, Le,Xu, Guangyu
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experimental part
p. 513 - 516
(2010/06/21)
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- Reduction of steroidal ketones with amine - Boranes
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Complexes of secondary amines with borane, R2NH·BH 3, surpass sodium borohydride as reducing agents for saturated and unsaturated steroidal 3-, 12-, 17-, and 20-ketones as regards chemo- and regioselectivity and mildness of the reaction conditions. In the case of 12-ketones, stereoselectivity is also improved.
- Leontjev,Vasiljeva,Pivnitsky
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p. 703 - 708
(2007/10/03)
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- Novel catalytic activity of immobilized spores under reduced water activity
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Onset of a new catalytic function during transformation of progesterone by immobilized spores of Aspergillus ochraceus TS under reduced water activity is reported. The pathway of transformation, which furnished 1,4-androstadien-17β-ol-3-one and 1,4-androstadien-3,17-dione due to cleavage of C17-C20 bond, is different from normal reaction sequence.
- Dutta, Tapan K.,Samanta, Timir B.
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p. 629 - 632
(2007/10/03)
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- Formation of 5α steroids by biotranformation involving the 5 α-reductase activity of Penicillium decumbens
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The biotransformation of a series of Δ4-3-ketosteroids by the Penicillium decumbens ATCC 10436 has been investigated. Conversion to the 5α-dihydrosteroid was observed substrates of the androsterone and pregne series: the reaction is tolerant of non-polar substituents (Cl and CH3) at C-4 of the substrate, but does not occur in the presence of a 4-hydroxyl group, or with additional unsaturation at the Δ1 or Δ6 positions. A-nor, B-nor, 3-deoxy-, and 3,5-cycloandrostanes are not reduced, but 6-methylenestestosterone is converted to a 6-methylene-5α-dihydro derivative. Several biotransformations are reported which involve oxidoreductase activity at C-3 and/or C-17, either concomitant or independent of Δ4 reduction: the substrate specificity of the oxidoreductase processes has been examined and defined by the use of 3α-hydroxy, 3β-hydroxy, 3-keto, 17β-keto substituted steroids. In this way, the existence in P. decumbens of 3β-hydroxy-3-keto and 17β-hydroxy-17-keto oxidoreductases has been demonstrated.
- Holland, Herbert L.,Dore, Sophia,Xu, Weili,Brown, Frances M.
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p. 642 - 647
(2007/10/02)
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- Stereoselective Reduction in the Biotransformation of Androstane Derivatives by Cell Suspension Cultures of Marchantia Polymorpha
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Cell suspension cultures of Marchantia polymorpha mainly convert 1,4-androstadiene-3,17-dione to 17β-hydroxy-1,4-androstadiene-3-one and adrenosterone to 17α-hydroxy-4-androstene-3,11-dione.
- Hamada, Hiroki,Naka, Shungo,Kurban, Halil
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p. 2111 - 2112
(2007/10/02)
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- ISOLATION AND THE STRUCTURE OF THE PRODUCTS OF CHOLESTEROL BIODEGRADATION BY THE MUTANT Mycobacterium sp. CCM 3529
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During the biodegradation of cholesterol by the mutant Mycobacterium sp.CCM 3529 1,4-androstadiene-3,17-dione (II) is formed as the main product.The following compounds were identified as characteristic by-products: a mixture of methyl esters IV and V in a 1:3 ratio, 4-androstene-3,17-dione (III), 22-hydroxy derivative I, 17β-hydroxy-4-androsten-3-one (XIII) and 17β-hydroxy-1,4-androstadien-3-one (XII).
- Mickova, Ruzena,Hutlova, Hana,Pihera, Pavel,Protiva, Jiri,Schwarz, Vladimir
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p. 1110 - 1113
(2007/10/02)
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- Microbiological Transformations. XVI. Transformation of 5α- and 5β-Dihydro, and 1- and 6-Dehydro Derivatives of Testosterone and Androstenedione by Means of Rhodotorula mucilaginosa Strain
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The following transformation of 5α- and 5β-dihydro derivatives of testosterone and androstenedione by means of Rhodotorula mucilaginosa has been observed: reduction of the carbonyl group on C-3 to both possible alcohols in the 5α-series and only to one alcohol (3α) in the 5β-series.In the transformation of 1- and 6-dehydro derivatives of testosterone and androstenedione, reduction in ring A was completely inhibited.The carbonyl or hydroxy groups at C-17 in both series of substrates underwent interconversion.
- Draczynska, Bozena,Tlomak, Elzbieta,Dmochowska-Gladysz, Jadwiga,Siewinski, Antoni
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