- Design of a self-sufficient hydride-shuttling cascade for concurrent bioproduction of 7,12-dioxolithocholate andl-tert-leucine
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Oxidoreductase-mediated biotransformation often requires consumption of a secondary sacrificial co-substrate and an additional auxiliary enzyme to drive the cofactor regeneration, which results in generation of unwanted by-product. Herein, we report a highly atom-economic self-sufficient hydride-shuttling cascade to concurrently obtain two pharmaceutically important building blocks (7,12-dioxo-lithocholic acid andl-tert-leucine) in which oxidation of cholic acid (CA) and reductive amination of trimethylpyruvic acid were integrated for redox self-recycling. In this cascade, the cofactor acts as a hydride shuttle that interconnects the two synthetically relevant reactions at the cost of only inorganic ammonium as the sacrificial agent and generates water as the greenest by-product. The preparative biotransformation using a whole-cell biocatalyst in the absence of any exogenous cofactor displayed a space-time yield of 768 g L?1d?1and a total turnover number (TTN) of 20?363 for NAD+recycling. This represents the highest cofactor TTN reported to date for the bio-oxidation of CA, indicating the great potential of this cofactor and redox self-sufficient bioprocess for cost-effective and sustainable biomanufacturing of high-value-added products.
- Chen, Qi,Han, Yu,Li, Chun-Xiu,Pan, Jiang,Qian, Xiao-Long,Xu, Jian-He,Yang, Bing-Yi,You, Zhi-Neng,Zhou, Ke
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supporting information
p. 4125 - 4133
(2021/06/17)
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- Clean Enzymatic Oxidation of 12α-Hydroxysteroids to 12-Oxo-Derivatives Catalyzed by Hydroxysteroid Dehydrogenase
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The C12 specific oxidation of hydroxysteroids is an essential reaction required for the preparation of pharmaceutical ingredients like ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA), which can be synthesized by Wolff-Kishner reduction of the obtained 12-oxo-hydroxysteroids. 12α-hydroxysteroid dehydrogenases (12α-HSDHs) have been shown to perform this reaction with high yields, under mild conditions and without the need of protection and deprotection steps, required in chemical synthesis. Here, the recombinant expression and biochemical characterization of the nicotinamide adenine dinucleotide (NAD+)-dependent HSDH from Eggerthella lenta (El12α-HSDH) are reported. This enzyme shows comparable properties with the well-known nicotinamide adenine dinucleotide phosphate (NADP+)-dependent enzyme from Clostridium sp. 48–50. In order to perform a viable and atom efficient enzymatic hydroxysteroid oxidation, NAD(P)H oxidase (NOX) was employed as cofactor regeneration system: NOX uses oxygen (O2) as sacrificial substrate and produces only water as side product. 10 mM of cholic acid was fully and selectively converted to 12-oxo-CDCA in 24 h. The possibility to employ this system on UCA and 7-oxo-deoxycholic acid (7-oxo-DCA) as substrates was additionally investigated. The performance of the El12α-HSDH was evaluated also in combination with a “classical” regeneration system (oxaloacetate/malate dehydrogenase) showing full conversion in 4 h. Finally, the feasibility of a catalytic aerobic-NAD+-dependent enzymatic oxidation was shown on a preparative scale (oxidation of CA to 12-oxo-CDCA) employing the El12α-HSDH-NOX system in a segmented-flow-reactor. (Figure presented.).
- Tonin, Fabio,Alvarenga, Natália,Ye, Jia Zheng,Arends, Isabel W. C. E.,Hanefeld, Ulf
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supporting information
p. 2448 - 2455
(2019/05/22)
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- Efficient Synthesis of 12-Oxochenodeoxycholic Acid Using a 12α-Hydroxysteroid Dehydrogenase from Rhodococcus ruber
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12α-Hydroxysteroid dehydrogenase (12α-HSDH) has the potential to convert cheap and readily available cholic acid (CA) to 12-oxochenodeoxycholic acid (12-oxo-CDCA), a key precursor for chemoenzymatic synthesis of the therapeutic bile acid ursodeoxycholic acid (UDCA). In this work, a native nicotinamide adenine dinucleotide (NAD+)-dependent 12α-hydroxysteroid dehydrogenase (Rr12α-HSDH) from Rhodococcus ruber was identified using a structure-guided genome mining (SSGM) approach, which is based on the structure of cofactor pocket and the conserved nicotinamide cofactor binding motif alignment. Rr12α-HSDH was heterologously overexpressed in Escherichia coli BL21 (DE3), purified and characterized. The purified Rr12α-HSDH showed a high oxidative activity of 290 U mg?1protein toward CA, with a catalytic efficiency (kcat/KM) of 5.10×103 mM?1 s?1. In a preparative biotransformation (100 mL), CA (200 mM, 80 g L?1) was efficiently converted to 12-oxo-CDCA in 1 h, with a 85% isolated yield and a space-time yield (STY) of up to 1632 g L?1 d?1. Furthermore, Rr12α-HSDH was shown to be able to catalyze the oxidation of other 12α-hydroxysteroids at high substrate loads (up to 200 mM), giving the corresponding 12-oxo-hydroxysteroids in 71%–85% yields, indicating the great potential of Rr12α-HSDH as a promising biocatalyst for the synthesis of various therapeutic bile acids. (Figure presented.).
- Shi, Shou-Cheng,You, Zhi-Neng,Zhou, Ke,Chen, Qi,Pan, Jiang,Qian, Xiao-Long,Xu, Jian-He,Li, Chun-Xiu
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supporting information
p. 4661 - 4668
(2019/09/10)
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- Regioselective oxidation of cholic acid and its 7β epimer by using o-iodoxybenzoic acid
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Rational exploration directed by DFT (density functional theory) based atomic Fukui indices, lead to development of regioselective oxidation of cholic acid and its 7β epimer by o-iodoxybenzoic acid. In case of cholic acid only, 7α-hydroxyl underwent oxidation, where as in its 7β epimer the selectivity was towards 12α-hydroxy group. Since these oxidations are the key steps in synthesis of ursodeoxycholic acid starting from cholic acid these findings may be useful in devising a protection free synthetic route.
- Dangate, Prasad S.,Salunke, Chetan L.,Akamanchi, Krishnacharya G.
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experimental part
p. 1397 - 1399
(2011/11/06)
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- 7α- and 12α-Hydroxysteroid dehydrogenases from Acinetobacter calcoaceticus lwoffii: a new integrated chemo-enzymatic route to ursodeoxycholic acid
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We report the very efficient biotransformation of cholic acid to 7-keto- and 7,12-diketocholic acids with Acinetobacter calcoaceticus lwoffii. The enzymes responsible of the biotransformation (i.e. 7α- and 12α-hydroxysteroid dehydrogenases) are partially purified and employed in a new chemo-enzymatic synthesis of ursodeoxycholic acid starting from cholic acid. The first step is the 12α-HSDH-mediated total oxidation of sodium cholate followed by the Wolf-Kishner reduction of the carbonyl group to chenodeoxycholic acid. This acid is then quantitatively oxidized with 7α-HSDH to 7-ketochenodeoxycholic acid, that was chemically reduced to ursodeoxycholic acid (70% overall yield).
- Giovannini, Pier Paolo,Grandini, Alessandro,Perrone, Daniela,Pedrini, Paola,Fantin, Giancarlo,Fogagnolo, Marco
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experimental part
p. 1385 - 1390
(2009/04/06)
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- Anodic electrochemical oxidation of cholic acid
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Regioselectivity in the anodic electrochemical oxidation of cholic acid with different anodes is described. The oxidation with PbO2 anode affords the dehydrocholic acid in quantitative yield after 22 h. 3α,12α-Dihydroxy-7-oxo-5β-cholan-24-oic acid (59%) and 3α-hydroxy-7,12-dioxo-5β-cholan-24-oic acid (51%) are obtained stopping the reaction at lower time. The rate of the OH-oxidation is C7 > C12 > C3. The electro-oxidation with platinum foil anode gives selectively the 7-ketocholic acid in 40% yield. On the other hand, the graphite plate anode, varying the reaction conditions, produces selectively the dehydrocholic acid in quantitative yield or the 3α,12α-dihydroxy-7-oxo-5β-cholan-24-oic acid (96%) while the 3α,7α-dihydroxy-12-oxo-5β-cholan-24-oic acid (34%) is obtained together with the other oxo acids. Copyright
- Medici, Alessandro,Pedrini, Paola,De Battisti, Achille,Fantin, Giancarlo,Fogagnolo, Marco,Guerrini, Alessandra
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- Regioselective microbial oxidation of bile acids
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High regioselectivity in the microbial oxidation of C7, C3 and C12 hydroxyl groups of cholic, chenodeoxycholic, deoxycholic and hyocholic acids 1-4 is reported. The tested microrganisms have been isolated from 50 environmental samples withdrawed from an industry that extracts and purify bile acids.
- Fantin, Giancarlo,Ferrarini, Sabina,Medici, Alessandro,Pedrini, Paola,Poli, Silvia
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p. 1937 - 1942
(2007/10/03)
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