Selective Biocatalysis
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Selective Biocatalysis
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Author : László Poppe
language : en
Publisher: Wiley-VCH
Release Date : 1992-07-06
Selective Biocatalysis written by László Poppe and has been published by Wiley-VCH this book supported file pdf, txt, epub, kindle and other format this book has been release on 1992-07-06 with Science categories.
László Poppe, Lajos Novák Selective Biocatalysis A Synthetic Approach This stimulating monograph is a much needed response to the increasing use of biocatalysts in organic synthesis. In over 300 well-referenced pages, it reviews in detail applications and other aspects of the most widely used enzymes (e.g. hydrolases, oxidoreductases, and baker’s yeast) illustrates with examples the potential in biocatalysis of other, less frequently used enzymes and microorganisms discusses general problems of biocatalysis (e.g. stereochemistry of transformations, methods of influencing selectivity) indicates future trends in biocatalysis Researchers and students in prcparative organic chemistry. biotechnology and biochemistry will find this up-to-date monograph highly valuable in their daily work.
Asymmetric And Selective Biocatalysis
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Author : Jose M. Palomo
language : en
Publisher: MDPI
Release Date : 2019-04-12
Asymmetric And Selective Biocatalysis written by Jose M. Palomo and has been published by MDPI this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-04-12 with Science categories.
This Issue contains one communication, six articles, and two reviews. The communication from Paola Vitale et al. represents a work where whole cells were used as biocatalysts for the reduction of optically active chloroalkyl arylketones followed by a chemical cyclization to give the desired heterocycles. Among the various whole cells screened (baker’s yeast, Kluyveromyces marxianus CBS 6556, Saccharomyces cerevisiae CBS 7336, Lactobacillus reuteri DSM 20016), baker’s yeast provided the best yields and the highest enantiomeric ratios (95:5) in the bioreduction of the above ketones. In this respect, valuable chiral non-racemic functionalized oxygen-containing heterocycles (e.g., (S)-styrene oxide, (S)-2-phenyloxetane, (S)-2-phenyltetrahydrofuran), amenable to be further elaborated on, can be smoothly and successfully generated from their prochiral precursors. Studies about pure biocatalysts with mechanistical studies, application in different reactions, and new immobilization methods for improving their stability were reported in five different articles. The article by Su-Yan Wang et al. describes the cloning, expression, purification, and characterization of an N-acetylglucosamine 2-epimerase from Pedobacter heparinus (PhGn2E). For this, several N-acylated glucosamine derivatives were chemically synthesized and used to test the substrate specificity of the enzyme. The mechanism of the enzyme was studied by hydrogen/deuterium NMR. The study at the anomeric hydroxyl group and C-2 position of the substrate in the reaction mixture confirmed the epimerization reaction via ring-opening/enolate formation. Site-directed mutagenesis was also used to confirm the proposed mechanism of this interesting enzyme. The article by Forest H. Andrews et al. studies two enzymes, benzoylformate decarboxylase (BFDC) and pyruvate decarboxylase (PDC), which catalyze the non-oxidative decarboxylation of 2-keto acids with different specificity. BFDC from Pseudomonas putida exhibited very limited activity with pyruvate, whereas the PDCs from S. cerevisiae or from Zymomonas mobilis showed virtually no activity with benzoylformate (phenylglyoxylate). After studies using saturation mutagenesis, the BFDC T377L/A460Y variant was obtained, with 10,000-fold increase in pyruvate/benzoylformate. The change was attributed to an improvement in the Km value for pyruvate and a decrease in the kcat value for benzoylformate. The characterization of the new catalyst was performed, providing context for the observed changes in the specificity. The article by Xin Wang et al. compares two types of biocatalysts to produce D-lysine L-lysine in a cascade process catalyzed by two enzymes: racemase from microorganisms that racemize L-lysine to give D,L-lysine and decarboxylase that can be in cells, permeabilized cells, and the isolated enzyme. The comparison between the different forms demonstrated that the isolated enzyme showed the higher decarboxylase activity. Under optimal conditions, 750.7 mmol/L D-lysine was finally obtained from 1710 mmol/L L-lysine after 1 h of racemization reaction and 0.5 h of decarboxylation reaction. D-lysine yield could reach 48.8% with enantiomeric excess (ee) of 99%. In the article by Rivero and Palomo, lipase from Candida rugosa (CRL) was highly stabilized at alkaline pH in the presence of PEG, which permitted its immobilization for the first time by multipoint covalent attachment on different aldehyde-activated matrices. Different covalent immobilized preparation of the enzyme was successfully obtained. The thermal and solvent stability was highly increased by this treatment, and the novel catalysts showed high regioselectivity in the deprotection of per-O-acetylated nucleosides. The article by Robson Carlos Alnoch et al. describes the protocol and use of a new generation of tailor-made bifunctional supports activated with alkyl groups that allow the immobilization of proteins through the most hydrophobic region of the protein surface and aldehyde groups that allows the covalent immobilization of the previously adsorbed proteins. These supports were especially used in the case of lipase immobilization. The immobilization of a new metagenomic lipase (LipC12) yielded a biocatalyst 3.5-fold more active and 5000-fold more stable than the soluble enzyme. The PEGylated immobilized lipase showed high regioselectivity, producing high yields of the C-3 monodeacetylated product at pH 5.0 and 4 °C. Hybrid catalysts composed of an enzyme and metallic complex are also treated in this Special Issue. The article by Christian Herrero et al. describes the development of the Mn(TpCPP)-Xln10A artificial metalloenzyme, obtained by non-covalent insertion of Mn(III)-meso-tetrakis(p-carboxyphenyl)porphyrin [Mn(TpCPP), 1-Mn] into xylanase 10A from Streptomyces lividans (Xln10A). The complex was found able to catalyze the selective photo-induced oxidation of organic substrates in the presence of [RuII(bpy)3]2+ as a photosensitizer and [CoIII(NH3)5Cl]2+ as a sacrificial electron acceptor, using water as oxygen atom source. The two published reviews describe different subjects with interest in the fields of biocatalysis and mix metallic-biocatalysis, respectively. The review by Anika Scholtissek et al. describes the state-of-the-art regarding ene-reductases from the old yellow enzyme family (OYEs) to catalyze the asymmetric hydrogenation of activated alkenes to produce chiral products with industrial interest. The dependence of OYEs on pyridine nucleotide coenzyme can be avoided by using nicotinamide coenzyme mimetics. In the review, three main classes of OYEs are described and characterized. The review by Yajie Wang and Huimin Zhao highlights some of the recent examples in the past three years that combine transition metal catalysis with enzymatic catalysis. With recent advances in protein engineering, catalyst synthesis, artificial metalloenzymes, and supramolecular assembly, there is great potential to develop more sophisticated tandem chemoenzymatic processes for the synthesis of structurally complex chemicals. In conclusion, these nine publications give an overview of the possibilities of different catalysts, both traditional biocatalysts and hybrids with metals or organometallic complexes to be used in different processes—particularly in synthetic reactions—under very mild reaction conditions.
Selective Biocatalysis
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Author : László Poppe
language : en
Publisher:
Release Date : 1992
Selective Biocatalysis written by László Poppe and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1992 with Biocatalysis categories.
Chemists from Hungary review and evaluate the widening application of selective, environment-friendly biocatalysts. They emphasize the most widely used enzymes, such as hydrolases, oxidoreductases, and baker's yeast; but provide examples of less frequently used enzymes and microorganisms, such as lyases and aldolases. Chapters also outline the basics of biotransformation and biocatalysis, and their stereochemical aspects. Fermentation processes, and the production of compounds by biotechnological methods are not covered. Annotation copyright by Book News, Inc., Portland, OR
Asymmetric And Selective Biocatalysis
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Author : Cesar Mateo
language : en
Publisher:
Release Date : 2019
Asymmetric And Selective Biocatalysis written by Cesar Mateo and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with categories.
This Issue contains one communication, six articles, and two reviews. The communication from Paola Vitale and others represents a work where whole cells were used as biocatalysts for the reduction of optically active chloroalkyl arylketones followed by a chemical cyclization to give the desired heterocycles. Among the various whole cells screened (baker's yeast, Kluyveromyces marxianus CBS 6556, Saccharomyces cerevisiae CBS 7336, Lactobacillus reuteri DSM 20016), baker's yeast provided the best yields and the highest enantiomeric ratios (95:5) in the bioreduction of the above ketones. In this respect, valuable chiral non-racemic functionalized oxygen-containing heterocycles (e.g., (S)-styrene oxide, (S)-2-phenyloxetane, (S)-2-phenyltetrahydrofuran), amenable to be further elaborated on, can be smoothly and successfully generated from their prochiral precursors. Studies about pure biocatalysts with mechanistical studies, application in different reactions, and new immobilization methods for improving their stability were reported in five different articles. The article by Su-Yan Wang and others describes the cloning, expression, purification, and characterization of an N-acetylglucosamine 2-epimerase from Pedobacter heparinus (PhGn2E). For this, several N-acylated glucosamine derivatives were chemically synthesized and used to test the substrate specificity of the enzyme. The mechanism of the enzyme was studied by hydrogen/deuterium NMR. The study at the anomeric hydroxyl group and C-2 position of the substrate in the reaction mixture confirmed the epimerization reaction via ring-opening/enolate formation. Site-directed mutagenesis was also used to confirm the proposed mechanism of this interesting enzyme. The article by Forest H. Andrews and others studies two enzymes, benzoylformate decarboxylase (BFDC) and pyruvate decarboxylase (PDC), which catalyze the non-oxidative decarboxylation of 2-keto acids with different specificity. BFDC from Pseudomonas putida exhibited very limited activity with pyruvate, whereas the PDCs from S. cerevisiae or from Zymomonas mobilis showed virtually no activity with benzoylformate (phenylglyoxylate). After studies using saturation mutagenesis, the BFDC T377L/A460Y variant was obtained, with 10,000-fold increase in pyruvate/benzoylformate. The change was attributed to an improvement in the Km value for pyruvate and a decrease in the kcat value for benzoylformate. The characterization of the new catalyst was performed, providing context for the observed changes in the specificity. The article by Xin Wang and others compares two types of biocatalysts to produce D-lysine L-lysine in a cascade process catalyzed by two enzymes: racemase from microorganisms that racemize L-lysine to give D,L-lysine and decarboxylase that can be in cells, permeabilized cells, and the isolated enzyme. The comparison between the different forms demonstrated that the isolated enzyme showed the higher decarboxylase activity. Under optimal conditions, 750.7 mmol/L D-lysine was finally obtained from 1710 mmol/L L-lysine after 1 h of racemization reaction and 0.5 h of decarboxylation reaction. D-lysine yield could reach 48.8% with enantiomeric excess (ee) of 99%. In the article by Rivero and Palomo, lipase from Candida rugosa (CRL) was highly stabilized at alkaline pH in the presence of PEG, which permitted its immobilization for the first time by multipoint covalent attachment on different aldehyde-activated matrices. Different covalent immobilized preparation of the enzyme was successfully obtained. The thermal and solvent stability was highly increased by this treatment, and the novel catalysts showed high regioselectivity in the deprotection of per-O-acetylated nucleosides. The article by Robson Carlos Alnoch and others describes the protocol and use of a new generation of tailor-made bifunctional supports activated with alkyl groups that allow the immobilization of proteins through the most hydrophobic region of the protein surface and aldehyde groups that allows the covalent immobilization of the previously adsorbed proteins. These supports were especially used in the case of lipase immobilization. The immobilization of a new metagenomic lipase (LipC12) yielded a biocatalyst 3.5-fold more active and 5000-fold more stable than the soluble enzyme. The PEGylated immobilized lipase showed high regioselectivity, producing high yields of the C-3 monodeacetylated product at pH 5.0 and 4 °C. Hybrid catalysts composed of an enzyme and metallic complex are also treated in this Special Issue. The article by Christian Herrero and others describes the development of the Mn(TpCPP)-Xln10A artificial metalloenzyme, obtained by non-covalent insertion of Mn(III)-meso-tetrakis(p-carboxyphenyl)porphyrin [Mn(TpCPP), 1-Mn] into xylanase 10A from Streptomyces lividans (Xln10A). The complex was found able to catalyze the selective photo-induced oxidation of organic substrates in the presence of [RuII(bpy)3]2+ as a photosensitizer and [CoIII(NH3)5Cl]2+ as a sacrificial electron acceptor, using water as oxygen atom source. The two published reviews describe different subjects with interest in the fields of biocatalysis and mix metallic-biocatalysis, respectively. The review by Anika Scholtissek and others describes the state-of-the-art regarding ene-reductases from the old yellow enzyme family (OYEs) to catalyze the asymmetric hydrogenation of activated alkenes to produce chiral products with industrial interest. The dependence of OYEs on pyridine nucleotide coenzyme can be avoided by using nicotinamide coenzyme mimetics. In the review, three main classes of OYEs are described and characterized. The review by Yajie Wang and Huimin Zhao highlights some of the recent examples in the past three years that combine transition metal catalysis with enzymatic catalysis. With recent advances in protein engineering, catalyst synthesis, artificial metalloenzymes, and supramolecular assembly, there is great potential to develop more sophisticated tandem chemoenzymatic processes for the synthesis of structurally complex chemicals. In conclusion, these nine publications give an overview of the possibilities of different catalysts, both traditional biocatalysts and hybrids with metals or organometallic complexes to be used in different processes-particularly in synthetic reactions-under very mild reaction conditions.
Biocatalysis
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Author :
language : en
Publisher:
Release Date : 1994
Biocatalysis written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1994 with Biochemical engineering categories.
Biocatalysis And Biomimetics
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Author : James D. Burrington
language : en
Publisher: Washington : American Chemical Society
Release Date : 1989
Biocatalysis And Biomimetics written by James D. Burrington and has been published by Washington : American Chemical Society this book supported file pdf, txt, epub, kindle and other format this book has been release on 1989 with Science categories.
Bridges the gap between chemical and biological catalysis. Reports on new developments in biocatalysis and biomimetic catalysis and explores future applications of catalysis in the chemical and biotechnology industries. Major themes include the use of computers in biocatalyst design; applications and properties of surface-bound enzymes; biomimetic catalysts and hybrid enzymes; and enzymes in organic solvents and reverse micelles. Focuses on both chemical and engineering aspects of novel biocatalytic systems, describing both fundamental and practical aspects.
Recent Advances In Selective Biocatalysis
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Author : Enzo Santaniello
language : en
Publisher:
Release Date : 2006
Recent Advances In Selective Biocatalysis written by Enzo Santaniello and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006 with categories.
Current Organic Chemistry
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Author :
language : en
Publisher:
Release Date : 2009
Current Organic Chemistry written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with Asymmetric synthesis categories.
Provides in depth reviews on current progress in the fields of asymmetric synthesis, organometallic chemistry, bioorganic chemistry, heterocyclic chemistry, natural product chemistry, and analytical methods in organic chemistry. Each issue is edited by an appointed Executive Guest Editor
Applied Biocatalysis In Specialty Chemicals And Pharmaceuticals
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Author : Badal C. Saha
language : en
Publisher:
Release Date : 2001
Applied Biocatalysis In Specialty Chemicals And Pharmaceuticals written by Badal C. Saha and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2001 with Language Arts & Disciplines categories.
Written for a wide variety of biotechnologists, this book provides a major review of the state-of-the-art in bioethanol production technologies, enzymatic biomass conversion, and biodiesel. It also provides a detailed explanation of a breakthrough in photosynthetic water splitting which could result in a doubling of the efficiency of solar energy conversion by green plants. The book covers production of lactic acid, succinic acid, 1,3-propanediol, 2,3-butanediol, and polyhydroxybutyrate and xylitol. It also includes a chapter on synthesis-gas fermentation.
Nonaqueous Biocatalysis In The Synthesis Of Focused Diversity
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Author : David Henry Altreuter
language : en
Publisher:
Release Date : 2001
Nonaqueous Biocatalysis In The Synthesis Of Focused Diversity written by David Henry Altreuter and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2001 with categories.