Home About us Contact
|
Home About us Contact | ||
|
|
||
Benzaldehyde Lyase (benzaldehyde + lyase)
Selected AbstractsMixed Aromatic Acyloin Condensations with Recombinant Benzaldehyde Lyase: Synthesis of ,-Hydroxydihydrochalcones and Related ,-Hydroxy KetonesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 6-7 2003Monica Sanchez-Gonzalez Abstract Recombinant benzaldehyde lyase (BAL), expressed and purified from E.,coli strain JM-109, was used to catalyze the condensation of a series of methoxybenzaldehydes and phenylacetaldehyde in the synthesis of ,-(R)-hydroxydihydrochalcones. Enantiomerically pure 1-hydroxy-1,3-diphenylpropan-2-ones and o -anisoin were also obtained as products of the BAL reaction. The R absolute configurations of chiral centers were determined by CD spectroscopy. ,-(R)-Hydroxydihydrochalcones and 1-hydroxy-1,3-diphenylpropan-2-ones are valuable synthons for chemoenzymatic syntheses of flavonoids. This is the first synthesis of ,-(R)-hydroxydihydrochalcones by a microbial enzyme. [source] Factors Mediating Activity, Selectivity, and Substrate Specificity for the Thiamin Diphosphate-Dependent Enzymes Benzaldehyde Lyase and Benzoylformate DecarboxylaseCHEMBIOCHEM, Issue 12 2006Michael Knoll Abstract Benzaldehyde lyase from Pseudomonas fluorescens and benzoylformate decarboxylase from Pseudomonas putida are homologous thiamin diphosphate-dependent enzymes that catalyze carboligase and carbolyase reactions. Both enzymes catalyze the formation of chiral 2-hydroxy ketones from aldehydes. However, the reverse reaction has only been observed with benzaldehyde lyase. Whereas benzaldehyde lyase is strictly R specific, the stereoselectivity of benzoylformate decarboxylase from P. putida is dependent on the structure and orientation of the substrate aldehydes. In this study, the binding sites of both enzymes were investigated by using molecular modelling studies to explain the experimentally observed differences in the activity, stereo- and enantioselectivity and substrate specificity of both enzymes. We designed a detailed illustration that describes the shape of the binding site of both enzymes and sufficiently explains the experimental effects observed with the wild-type enzymes and different variants. These findings demonstrate that steric reasons are predominantly responsible for the differences observed in the (R)-benzoin cleavage and in the formation of chiral 2-hydroxy ketones. [source] Structure of the ThDP-dependent enzyme benzaldehyde lyase refined to 1.65,Å resolutionACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 7 2007Andy Maraite Benzaldehyde lyase (BAL; EC 4.1.2.38) is a thiamine diphosphate (ThDP) dependent enzyme that catalyses the enantioselective carboligation of two molecules of benzaldehyde to form (R)-benzoin. BAL has hence aroused interest for its potential in the industrial synthesis of optically active benzoins and derivatives. The structure of BAL was previously solved to a resolution of 2.6,Å using MAD experiments on a selenomethionine derivative [Mosbacher et al. (2005), FEBS J.272, 6067,6076]. In this communication of parallel studies, BAL was crystallized in an alternative space group (P212121) and its structure refined to a resolution of 1.65,Å, allowing detailed observation of the water structure, active-site interactions with ThDP and also the electron density for the co-solvent 2-methyl-2,4-pentanediol (MPD) at hydrophobic patches of the enzyme surface. [source] Factors Mediating Activity, Selectivity, and Substrate Specificity for the Thiamin Diphosphate-Dependent Enzymes Benzaldehyde Lyase and Benzoylformate DecarboxylaseCHEMBIOCHEM, Issue 12 2006Michael Knoll Abstract Benzaldehyde lyase from Pseudomonas fluorescens and benzoylformate decarboxylase from Pseudomonas putida are homologous thiamin diphosphate-dependent enzymes that catalyze carboligase and carbolyase reactions. Both enzymes catalyze the formation of chiral 2-hydroxy ketones from aldehydes. However, the reverse reaction has only been observed with benzaldehyde lyase. Whereas benzaldehyde lyase is strictly R specific, the stereoselectivity of benzoylformate decarboxylase from P. putida is dependent on the structure and orientation of the substrate aldehydes. In this study, the binding sites of both enzymes were investigated by using molecular modelling studies to explain the experimentally observed differences in the activity, stereo- and enantioselectivity and substrate specificity of both enzymes. We designed a detailed illustration that describes the shape of the binding site of both enzymes and sufficiently explains the experimental effects observed with the wild-type enzymes and different variants. These findings demonstrate that steric reasons are predominantly responsible for the differences observed in the (R)-benzoin cleavage and in the formation of chiral 2-hydroxy ketones. [source] Mixed Aromatic Acyloin Condensations with Recombinant Benzaldehyde Lyase: Synthesis of ,-Hydroxydihydrochalcones and Related ,-Hydroxy KetonesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 6-7 2003Monica Sanchez-Gonzalez Abstract Recombinant benzaldehyde lyase (BAL), expressed and purified from E.,coli strain JM-109, was used to catalyze the condensation of a series of methoxybenzaldehydes and phenylacetaldehyde in the synthesis of ,-(R)-hydroxydihydrochalcones. Enantiomerically pure 1-hydroxy-1,3-diphenylpropan-2-ones and o -anisoin were also obtained as products of the BAL reaction. The R absolute configurations of chiral centers were determined by CD spectroscopy. ,-(R)-Hydroxydihydrochalcones and 1-hydroxy-1,3-diphenylpropan-2-ones are valuable synthons for chemoenzymatic syntheses of flavonoids. This is the first synthesis of ,-(R)-hydroxydihydrochalcones by a microbial enzyme. [source] Operational concept for the improved synthesis of (R)-3,3'-furoin and related hydrophobic compounds with benzaldehyde lyaseBIOTECHNOLOGY JOURNAL, Issue 5 2006Marion B. Ansorge-Schumacher Dr. Abstract Biphasic reaction systems for enzyme catalysis are an elegant way to overcome limited solubility and stability of reactants and facilitate continuous processes. However, many synthetically useful enzymes are not stable in biphasic systems of water and organic solvent. The entrapment in polymer beads of polyvinyl alcohol has been shown to enable the stable operation of enzymes unstable in conventional biphasic reaction systems. We report the extension of this concept to continuous operation in a fluidised bed reactor. The enzyme benzaldehyde lyase was used for the continuous synthesis of enantiopure (R)-3,3'-furoin. The results show enhanced stability with half-life times under operation conditions of more than 100 h, as well as superior enzyme utilisation in terms of productivity. Furthermore, racemisation and oxidation of the product could be successfully prevented under the non-aqueous and inert reaction conditions. [source] Structure of the ThDP-dependent enzyme benzaldehyde lyase refined to 1.65,Å resolutionACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 7 2007Andy Maraite Benzaldehyde lyase (BAL; EC 4.1.2.38) is a thiamine diphosphate (ThDP) dependent enzyme that catalyses the enantioselective carboligation of two molecules of benzaldehyde to form (R)-benzoin. BAL has hence aroused interest for its potential in the industrial synthesis of optically active benzoins and derivatives. The structure of BAL was previously solved to a resolution of 2.6,Å using MAD experiments on a selenomethionine derivative [Mosbacher et al. (2005), FEBS J.272, 6067,6076]. In this communication of parallel studies, BAL was crystallized in an alternative space group (P212121) and its structure refined to a resolution of 1.65,Å, allowing detailed observation of the water structure, active-site interactions with ThDP and also the electron density for the co-solvent 2-methyl-2,4-pentanediol (MPD) at hydrophobic patches of the enzyme surface. [source] Factors Mediating Activity, Selectivity, and Substrate Specificity for the Thiamin Diphosphate-Dependent Enzymes Benzaldehyde Lyase and Benzoylformate DecarboxylaseCHEMBIOCHEM, Issue 12 2006Michael Knoll Abstract Benzaldehyde lyase from Pseudomonas fluorescens and benzoylformate decarboxylase from Pseudomonas putida are homologous thiamin diphosphate-dependent enzymes that catalyze carboligase and carbolyase reactions. Both enzymes catalyze the formation of chiral 2-hydroxy ketones from aldehydes. However, the reverse reaction has only been observed with benzaldehyde lyase. Whereas benzaldehyde lyase is strictly R specific, the stereoselectivity of benzoylformate decarboxylase from P. putida is dependent on the structure and orientation of the substrate aldehydes. In this study, the binding sites of both enzymes were investigated by using molecular modelling studies to explain the experimentally observed differences in the activity, stereo- and enantioselectivity and substrate specificity of both enzymes. We designed a detailed illustration that describes the shape of the binding site of both enzymes and sufficiently explains the experimental effects observed with the wild-type enzymes and different variants. These findings demonstrate that steric reasons are predominantly responsible for the differences observed in the (R)-benzoin cleavage and in the formation of chiral 2-hydroxy ketones. [source] | ||||||||||