Synthesis of naturally occurring noctyl PDglucopyranosides22

The Chinese natural medicine Si Lie Hong Jing Tian prepared from the underground part of R. (R.) quadrifida (PALL.) Fisch. et Mey. has been prescribed for hemostatic, antibechic and tonic purposes in Chinese traditional preparations and used as an endermic liniment for burns and contusions. Rhodiooctanoside (99) was isolated as one of the chemical constituents of R. quadrifida by M. Yoshikawa et al. and found to show potent histamine release inhibitory activity. The structure of 99 was...

Class I decarboxylases

In the aligned primary structures of class I decarboxylases, the conserved amino acid residues are scattered over their primary structures. There have been few reports to identify the amino acid residues essential for catalytic activity or substrate binding. Huang et al.56 reported the E-X-P motif in the alignment analysis for 4-hydroxybenzoate decarboxylase of C. hydroxybenzoicum and its homologous unidentified proteins. The E-X-P motif is also conserved in pyrrole-2-carboxylate decarboxylase...

Conclusions

Work to date has shown the high potential of dehydrogenases as catalysts for asymmetric organic synthesis. Efforts to utilize new genomic resources are just coming to fruition and it seems clear that future progress will make even greater use of this information. This will drive demand for methods that allow a large number of candidate proteins to be evaluated quickly and easily. Fortunately, all the pieces needed for the required technological advances in this area appear to be in place...

Stereocontrolled transformations of organophosphorus acid esters

A variety of phosphoric acid triesters and their derivatives are used as pesticides. Although there are no natural phosphorotriesters, those artificial ones undergo decomposition in the soil, implying that some microorganisms exist which are capable of hydrolysing them. The first report on a stereoselective enzymatic phos-photriester hydrolysis was published in 1973, when Dudman and Zerner succeeded Enzymatic acetylation of hydroxymethylphosphine P-boranes Enzymatic acetylation of...

Screening For Heatstable Nhase

It goes without saying that not all microorganisms have been isolated by human beings. Once there is a report on a new enzyme produced by mesophiles, thermostable enzymes catalyzing the same reaction could be sought from the environment. To seek for thermophilic microorganisms, volcano, hot springs, chimneys at the bottom of the sea, etc., are the sources of isolation of such microorganisms. With the increasing knowledge in genomic information, screening for new bio-catalysts based on various...

Pchiral hydroxy phosphorus Pboranes

Among the useful chiral organophosphorus compounds, the trivalent derivatives play a special role. They are used both as chiral auxiliaries in stoichiometric reactions and as chiral ligands in transition metal catalysts. However, trivalent phosphorus compounds are prone to oxidation and usually difficult to handle. Therefore, their borane complexes, which are stable and which can be easily converted into the parent compounds without racemization, are becoming more and more popular.9697 Among...

Synthesis of geranyl PDglycopyranoside20

Monoterpene glycosides are a group of water-soluble natural products widely distributed in the plant kingdom. Among them, two kinds of naturally occurring geranyl 6-O-glucosyl-P-D-glucopyranoside congeners, geranyl (82) and geranyl (Kenposide A, 83) were isolated from a methanol extract of Camellia sinensis var. sinensis cv Shuixian and an ethanol extract of Hovenia dulsis var. tomentella, respectively. The biological activity of some compounds has been investigated and 83 is reported to...

IL r it

Figure 10 Lipase-catalyzed acylation the reaction depended on the counter A mixed solvent system of an IL with organic solvent sometimes gave very nice results Lundell21 reported that enhanced enantioselectivity was obtained when lipase-catalyzed acylation was carried out in a mixed solvent system of emim TFSI with t-BuOMe (1 1), while poor enantioselectivity was recorded for that in the pure emim TFSI solvent (Fig. 11). Ganske and co-workers22a b reported that lipase-catalyzed acylation of a...

Dihydroxybenzoate decarboxylase

2,3-Dihydroxybenzoate decarboxylase has been reported to be involved in the metabolism of indole, tryptophan, and anthranilic acid.4041 The primary structure of 2,3-dihydroxybenzoate decaroboxylase of Aspergillus niger has been revealed by gene analysis, which exhibits significant homology with those of 2,6-dihydroxybenzoate decarboxylases (unpublished data). This suggests that 2,3-dihydroxybenzoate decarboxylase also catalyzes the regioselective carboxylation of catechol to...

Structure Analysis Of Decarboxylases Catalyzing Co2 Fixation

Up to now, primary structures of the following enzymes catalyzing CO2 fixation have been revealed from nucleotide sequencing of their genes 4-hydroxybenzoate decarboxylase,2556 3,4-dihydroxybenzoate decarboxylase,26 pyrrole-2-carboxylate decarboxylase (unpublished data), indole-3-carboxylate decarboxylase (unpublished data), and 2,6-dihydroxybenzoate decarboxylase.3738 As for 2,3-dihydroxybenzoate decarboxylase, the carboxylation activity for catechol has not been reported. However, we presume...

Enzymes Catalyzing The Carboxylation Of Phenolic Compounds

Phenol is an important intermediate in the anaerobic degradation of many complex and simple aromatic compounds. Tschech and Fuchs15 proposed that the carboxylation of phenol to 4-hydroxybenzoate is the first step in the degradation of phenol under denitrifying conditions. However, 4-hydroxybenzoate is not detected in the cultures or cell extracts of the denitrifying Pseudomonas species in the presence of CO2 and phenol,8 but it is detected if phenol is replaced by phenolphosphate.16 In...

Pchiral phosphoroacetates

Resolution of various racemic P-chiral phosphorylacetates 70 involved the same approach as was shown for sulfinylcarboxylates (Scheme 2). However, unlike the case of sulfinyl compounds, only PLE proved efficient for their P(O) analogues. Thus, a series of racemic phosphinylacetates,83'84 phosphonylacetates85'86 and phos-phorylacetates85'86 were resolved into enantiomers via their PLE-promoted hydrolysis to give products in high yields and with high ees (Equation 33). The most representative,...

Pyrrole2carboxylate decarboxylase

B. megaterium PYR2910, isolated from soil for its ability to grown on pyrrole-2-carboxylate as the sole source of carbon and energy, produces a novel enzyme, pyrrole-2-carboxylate decarboxylase, to catalyze the decarboxylation of pyrrole-2-carboxylate into pyrrole and CO2.43 Thiophene-2-carboxylate and L-thioproline (each 0.2 , w v), which are analogous to the substrate pyrrole-2-carboxylate but not converted by the enzyme, were found to be the most effective enzyme inducers, leading to 3-fold...

O

PEG was found to be a template in the oxidative polymerization of phenol in water.174 175 The presence of the PEG template in an aqueous medium greatly improved the regioselectivity of the polymerization, yielding a phenol polymer with the phenylene unit content higher than 90 . During the reaction, the polymer was produced in high yields as precipitates in complexing with PEG. The molecular weight of PEG strongly affected the polymer yield. The unit molar ratio of polyphone and PEG was ca. 1...

Purification of the enzyme and cloning of the gene

Although the absolute configurations of the products are opposite to that of antiinflammatory active compounds, and the substrate specificity is rather restricted as to the steric bulkiness around the reaction center, the enzyme system of A. bronchisepticus was proved to have a unique reactivity. Thus, detailed studies on the isolated enzyme were expected to elucidate some new interesting mechanism of the new type of decarboxylation. Thus, the enzyme was purified. (The enzyme is now registered...

Application of decarboxylation reaction to dialkylmalonates

The asymmetric decarboxylation of arylmethylmalonic acid catalyzed by AMDase is a unique and useful reaction for the synthesis of optically active aryl propionic acids. However, the most serious drawback of this reaction is that it cannot be applied to dialkylmalonates. Dialkylmalonates are readily available from non-substituted malonic acid via malonic ester synthesis. If asymmetric decarboxylation of this type of compounds is developed, it will be quite useful for the synthesis of carboxylic...

Artificial urushi

As japan implies the meaning of a lacquer or varnish giving a hard, glossy finish and or objects decorated and lacquered in the Japanese style,205 urushi wares are regarded as one of the most typical symbols of Japanese art. Oriental lacquer (urushi) of Japan and China is a natural resinous sap of the Rhus vernicifera tree. Urushi coating is hard enough to give a brilliant polish and is highly durable (for more than a thousand years under appropriate conditions) and solvent-resistant in...

References

Biol. Chem. 1963, 238, 2875-2833. 2. Kim, Y. S. Kolattukudy, P. E. J. Biol. Chem. 1980, 2JJ, 686-889. 3. Kackowsky, J. Mazeto-Toczko, M. Acta Microc. Polon. 1960, 9, 173-179. 4. Thomas, N. R. Schirch, V. Gani, D. J. Chem. Soc. Chem. Commun.1990, 400-402. 5. Thomas, N. R. Rose, J. E. Gani, D. J. Chem. Soc. Chem. Commun.1991, 908-909. 6. (a) Walker, J. A. US Patent 4266069 Chem. Abstr. 1981, 9J, 80497. (b) Hylton, T. A. Walker, J. A. Eur. Patent 32620 Chem....

A

Figure 6 Enantioselective oxidation of secondary alcohols with secondary alcohol dehydrogenase (SADH), from a thermophilic bacterium (log E is used in Figure 6 Enantioselective oxidation of secondary alcohols with secondary alcohol dehydrogenase (SADH), from a thermophilic bacterium (log E is used in a similar reaction with 2-pentanol raised the Tr to 70 C, and that with 2-hexanol further raised the Tr to 260 0C. These results suggest that the chain length changes the structure of the...

Enzymatic synthesis of functional phenolic polymers

Poly(2,6-dimethyl-1,4-oxyphenylene) (poly(phenylene oxide), PPO) is a material widely used as high-performance engineering plastics, thanks to its excellent chemical and physical properties, e.g., a high T (ca. 210 C) and mechanically tough property.151 PPO was first prepared from 2,6-dimethylphenol monomer using a copper amine catalyst system. 2,6-Dimethylphenol was also polymerized via HRP catalysis to give a polymer exclusively consisting of 1,4-oxyphenylene unit,177 while small amounts of...

Enzymatic oxidative polymerization of phenols

Peroxidase-catalyzed oxidative coupling of phenols proceeds fast in aqueous solutions, giving rise to the formation of oligomeric compounds. However, the resulting oligomers have not been well characterized, since most of them show low solubility towards common organic solvents and water. In 1987, enzymatic synthesis of a new class of phenolic polymers was first reported.150 An oxidative polymerization of p-phenylphenol using HRP as catalyst was carried out in a mixture of water and...

Reaction of allyl tetraacetyl fDglucopyranoside and phenyl boronic acid2425

Golden root (Roseroot, Rhodiola rosea L., Crassulaceae) has been used for a long time as a resource in Chinese traditional medicine. Phenylpropenoid glu-coside, such as Rosin (cinnamyl O-P-D-glucopyranoside 118a), was isolated from R. rosea as one of the major active ingredients and reported to be pharmacologically active as antioxidants and neurostimulants. Moreover, some other phenylpropenoid glucoside analogs have been isolated as bioactive substances. For instance, Sachaliside 1 (Triandrin...

Cchiral amino phosphorus compounds

C-Chiral amino phosphorus compounds, particularly 1-amino- and 2-aminoalkanephosphonic acids, have been a subject of interest for organic chemists due to their interesting biological activity.1cd Among many methods of their stereoselective synthesis, some enzymatic approaches have been reported, which constitute a nice alternative to chemical procedures. Stereoselective hydrolysis of racemic 1-(N-phenylacetylamino) alkanephos-phonic acids performed in the presence of penicillin acylase under...

Polycondensation of dicarboxylic acid derivatives and glycols to polyesters

So far, various dicarboxylic acid derivatives, dicarboxylic acids, their activated and non-activated esters, cyclic acid anhydrides, and polyanhydrides have been polymerized with glycols through lipase catalysis to give polyesters. Many diacids are commercially available however, their enzymatic reactivity is relatively low. Therefore, the enzymatic polymerization of dicarboxylic acids and glycols was often carried out under vacuum for production of high molecular weight polyesters.56 57 In the...

Enzymatic synthesis and biological properties of flavonoid polymers

Bioactive polyphenols are present in a variety of plants and used as important components of human and animal diets.215 Flavonoids are a broad class of low molecular weight secondary plant polyphenolics, which are benzo-7-pyrone derivatives consisting of phenolic and pyrane rings. Their biological and pharmacological effects including antioxidant, antimutagenic, anticarcinogenic, antiviral, and anti-inflammatory properties have been demonstrated in numerous human, animal, and in vitro studies....

Ringopening polymerization to polyesters

Various cyclic esters have been subjected to lipase-catalyzed ring-opening polymerization. Lipase catalyzed the ring-opening polymerization of 4- to 17-membered non-substituted lactones.16-18 In 1993, it was first demonstrated that medium-size lactones, 8-valerolactone 8-VL, six-membered and e-caprolactone e-CL, seven-membered , were polymerized by lipases derived from Candida cylindracea, Burkholderia cepacia lipase BC , Pseudomonas fluorescens lipase PF , and porcine pancreas PPL .1920...

Enzymatic synthesis of functional polyesters

Lipase catalysis is often used for enantioselective production of chiral compounds. Lipase induced the enantioselective ring-opening polymerization of racemic lactones. In the lipase-catalyzed polymerization of racemic P-BL, the enantioselec-tivity was low an enantioselective polymerization of P-BL occurred by using thermophilic lipase to give R -enriched PHB with 20-37 enantiomeric excess The enantioselectivity was greatly improved by the copolymerization with 7- or 13-membered non-substituted...

Possible use of enzymes for the direct carboxylation of organic substrates

Department of Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido, Gifu, Japan The occurrence of the enzymes catalyzing the Kolbe-Schmitt carboxylation has been shown, and the characterization of these enzymes has been reviewed. Among them, 2,6-dihydroxybenzoate decarboxylase and pyrrole-2-carboxylate decarboxylase efficiently catalyze the reverse carboxylation reaction and accumulate high concentration of 2,6-dihydroxybenzoate from 1,3-dihydroxybenzene and...

Oxidative decarboxylation of hydroxycarboxylic acids

As mentioned in the introductory part, stereochemical course of the conversion of isocitric acid to a-ketoglutaric acid in TCA cycle is completely enantiose-lective although the reaction does not form an asymmetric carbon in the usual metabolic path. If such type of oxidative decarboxylation can be applied to synthetic compounds, it is expected that an entirely new type of asymmetric biotransformation will be developed. Aiming at the feasibility study of such type of asymmetric decarboxylation,...

Tertiary structure and mutagenesis studies

TKase is a homodimeric protein with a subunit of about 70 kDa. The X-ray structures of TKase of E. coli,62 S. cerevisiae,61-63 67 Leishmania mexicana6 amp and mize69 have been solved. In addition, the crystal structures of a number of site-directed mutants have been determined.70-73 Schneider and co-workers have reported a series of studies in which they have mutated important residues of active site of TKase to elucidate the reaction mechanism and explain the origin of the stere-ospecificity...

Biocatalytic Properties Of Recombinant Available Bvmos

The list of heterologously expressed type I BVMOs has grown significantly in recent years Table 1 . Except for BVMOs primarily acting on small cyclic ketones cyclopentanone and cyclohexanone 1920, variants specific for larger cyclic ketones cyclododecanone and cyclopentadecanone have also been discovered.2122 Additionally, BVMOs that readily accept aromatic ketones 4-hydroxyacetophenone and phenylacetone derivatives have been described.1723 Also, a BVMO acting on steroids has been reported.24...

Conclusions Future Directions

As each BVMO is limited in substrate specificity, it is crucial to have a large collection of these oxidative biocatalysts available. Except for expanding the scope of possible reactions, a large toolbox of BVMOs would also increase the chance of being able to perform any wanted specific chemo-, regio- and or enantioselective reaction. This contrasts with the present situation as only a relatively small number of BVMOs can be exploited for biocatalytic purposes. Therefore, it is still crucial...

Introduction

The Baeyer-Villiger oxidation reaction was discovered more than 100 years ago by Adolf von Baeyer and Victor Villiger.1 By this reaction, ketones are converted into the corresponding esters. In organic chemistry, peracids are commonly used as catalyst to perform this atypical oxidation reaction that results in oxygen insertion into a carbon carbon bond Fig. 1 . Already in 1948 it was recognized that enzymes that catalyze Baeyer-Villiger reactions exist.2 This was concluded from the observation...

Future Directions in Biocatalysis

Tokyo Institute of Technology, Yokohama, Japan Amsterdam Boston Heidelberg London New York Oxford Paris San Diego San Francisco Singapore Sydney Tokyo Radarweg 29, PO Box 211, 1000 AE Amsterdam, The Netherlands Linacre House, Jordan Hill, Oxford OX2 8DP, UK Copyright 2007 Elsevier B.V. All rights reserved No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means electronic, mechanical, photocopying, recording or otherwise without the...

Hydroxybenzoate decarboxylase EC 41161

4-Hydroxybenzoate decarboxylase EC 4.1.1.61 of anaerobe C. hydroxyben-zoicum was purified and characterized for the first time.20 It has an apparent molecular mass of 350 kDa and consists of six identical subunits of 57 kDa. The temperature optimum for the decarboxylation is approximately 50 C, the optimum pH being 5.6-6.2. The activation energy for decarboxylation of 4-hydroxybenzoate is 65kJmol-1 20-37 C . The enzyme also catalyzes the decarboxylation of 3,4-dihydroxybenzoate. The apparent Km...

Redesign of BVMOs

For enzyme redesign studies, structural information of a targeted biocatalyst is very valuable. However, at present, no structure of the well-studied BVMO, CHMO, is available. In order to obtain a predictive structural model of the active site of CHMO, a cubic space model has been built based on the substrate acceptance of this biocatalyst.53 While this model can predict to some extent the specificity and selectivity of CHMO, it is of little use for enzyme redesign studies. However, even if no...

Discovery of novel BVMOs

While the number of available recombinant BVMOs has grown significantly over the last few years, there is still a demand for other BVMOs to expand the biocat-alytic diversity. Most BVMOs that have been described are dedicated to efficiently Figure 3 Illustration of overlapping substrate specificities of four BVMOs. Cyclohexanone monooxygenase CHMO , cyclopentanone monooxygenase CPMO , 4-hydroxyacetophenone monooxygenase HAPMO and phenylacetone monooxygenase PAMO . For each enzyme, several...

Crystal Structures Of Hydroxynitrile Lyases And Mechanism Of Cyanogenesis

The properties and characteristics of the five HNLs used as catalysts in stereoselective syntheses are listed in Table 2. The crystal structures of these HNLs have been determined during the last decade. From the crystal structures and kinetic measurements, the mechanistic pathways of cyanogenesis could be established. HNL-catalyzed addition of HCN to 4-substituted cyclohexanones R CN S -MeHNL R U M R -PaHNL R OH Scheme 9 Stereoselective synthesis of cis-p-menthane-1,7,8-triol A and...

Exploring sequenced metagenomes for novel BVMOs

Nowadays, the genomes of a wide variety of organisms have been sequenced and are publicly available, offering a new and efficient way of retrieving BVMO genes. Currently, as genome sequences of over 600 microbes are available see it is attractive to look directly into this pool of genes in silico without growing and isolating any microorganism. In addition to the database of partially and fully sequenced genomes, it is also informative to survey the database of sequenced environmental genomes....

Screening For New Microbial Enzymes By Enrichment And Acclimation Culture Techniques

Little is known about the substrate specificities of most of the enzymes as compared with common reagents used in organic synthesis. The velocity of the enzymatic reactions is much affected by the neighboring substituents it cannot be predicted whether an unnatural chemical can be a substrate or not with most of the enzymes. Therefore, we screen microorganisms for an enzyme when i no information is available for the desirable reaction, ii nothing is known about the specific reaction but a...

Screening the metagenome for novel BVMOs

Except for exploring sequenced genomes, yet other interesting approaches for discovering novel BVMOs exist. A recent development in the area of biocatalyst discovery is the exploitation of metagenomic DNA libraries. By this methodology, DNA is directly isolated from a certain sample that is expected to contain a variety of microbes e.g., soil . Subsequently, the obtained DNA is randomly fragmented and cloned into a suitable vector and expression host. The resulting gene library, containing a...

Stereoselective synthesis of substituted cyclohexanone cyanohydrins

Substituted 1-hydroxy cyclohexane-1-carboxylic acids, which could be prepared from the corresponding cyanohydrins by acid hydrolysis as described above, are important as pharmaceuticals and plant-protective agents.33 Although the compounds derived from 2- and 3-cyclohexanones have two stereogenic centers, stereoselective syntheses of these interesting products have been published only very recently.34 Completely unexpected are the results of HNL-catalyzed additions to 4-substituted...

Removal Of Organic And Inorganic Substances In Wastewater

The prudent disposal of large quantities of agricultural and domestic wastewaters is a major concern in our modern society. Raw wastewaters most often contain significant amounts of bioavailable organic substances such as phenols, endocrine disrupters, and inorganic substances such as ammoniate, nitrate, and phosphate. To remove these substances, algae and microalgae were used.18 For example, inorganic substances such as ammonium,19 phosphorous,18 and arsenate20 compounds and organic substances...

Biotransformation in ionic liquid

Department of Materials Science, Faculty of Engineering, Tottori University, Tottori, Japan The use of ionic liquids ILs to replace organic or aqueous solvents in biocatalysis processes has recently gained much attention and great progress has been accomplished in this area lipase-catalyzed reactions in an IL solvent system have now been established and several examples of biotransformation in this novel reaction medium have also been reported. Recent developments in the application of ILs as...

Phenolphosphate carboxylase EC 411 in Thauera aromatica

Hydroxybenzoate Decarboxylase

The anaerobic metabolism of phenol in T. aromatica is initiated by the ATP-dependent conversion of phenol to phenylphosphate catalyzed by phenylphosphate synthase EC 2.7.9.- . The subsequent para carboxylation of phenylphosphate to 4-hydroxybenzoate is catalyzed by phenolphosphate carboxylase EC 4.1.1.- .8'29'30 Both enzyme activities are induced in cells grown anoxially on phenol and nitrate and not in cells grown on 4-hydroxybenzoate, the product of this process. Further metabolism of...