1301
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Abstract
We demonstrate that proteases can catalyze the ligation of peptidomimetic oligomers. The enzyme clostripain was used to facilitate the native ligation of N-substituted glycine oligomers, or peptoids. In addition to mediating the efficient condensation of two peptoid fragments, iterative ligation events were also performed, giving rise to concatenation products with molecular weights up to 20 kDa. Efficient ligation of peptoid foldamers may enable the chemical synthesis of biomimetic macromolecules capable of forming complex tertiary structures.
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Affiliation(s)
- Barney Yoo
- Department of Chemistry, New York University, 100 Washington Square East, New York, New York 10003-6688, USA
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1302
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Mori S, Yumoto H, Matsumi R, Nishigaki T, Ebara Y, Ueji SI. A method to greatly improve the enantioselectivity of lipase-catalyzed hydrolysis using sodium dodecyl sulfate (SDS) as an additive. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.tetasy.2005.10.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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1303
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Singh S, Banerjee U. Enantioselective hydrolysis of methoxyphenyl glycidic acid methyl ester [(±)-MPGM] by a thermostable and alkalostable lipase from Pseudomonas aeruginosa. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.molcatb.2005.07.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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1304
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Zhang W, Liu Y, Zheng H, Yang S, Jiang W. Improving the activity and stability of GL-7-ACA acylase CA130 by site-directed mutagenesis. Appl Environ Microbiol 2005; 71:5290-6. [PMID: 16151116 PMCID: PMC1214626 DOI: 10.1128/aem.71.9.5290-5296.2005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the present study, glutaryl-7-amino cephalosporanic acid acylase from Pseudomonas sp. strain 130 (CA130) was mutated to improve its enzymatic activity and stability. Based on the crystal structure of CA130, two series of amino acid residues, one from those directly involved in catalytic function and another from those putatively involved in surface charge, were selected as targets for site-directed mutagenesis. In the first series of experiments, several key residues in the substrate-binding pocket were substituted, and the genes were expressed in Escherichia coli for activity screening. Two of the mutants constructed, Y151alphaF and Q50betaN, showed two- to threefold-increased catalytic efficiency (k(cat)/K(m)) compared to wild-type CA130. Their K(m) values were decreased by ca. 50%, and the k(cat) values increased to 14.4 and 16.9 s(-1), respectively. The ability of these mutants to hydrolyze adipoyl 6-amino penicillinic acid was also improved. In the second series of mutagenesis, several mutants with enhanced stabilities were identified. Among them, R121betaA and K198betaA had a 30 to 58% longer half-life than wild-type CA130, and K198betaA and D286betaA showed an alkaline shift of optimal pH by about 1.0 to 2.0 pH units. To construct an engineered enzyme with the properties of both increased activity and stability, the double mutant Q50betaN/K198betaA was expressed. This enzyme was purified and immobilized for catalytic analysis. The immobilized mutant enzyme showed a 34.2% increase in specific activity compared to the immobilized wild-type CA130.
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Affiliation(s)
- Wei Zhang
- Laboratory of Molecular Microbiology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Rd., Shanghai 200032, People's Republic of China
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1305
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Sharma AK, Kumar R, Canteenwala TC, Parmar VS, Patkar S, Kumar J, Watterson AC. Biocatalytic Synthesis and Characterization of Copolymers Based on Poly(Ethylene Glycol) and Unsaturated Methyl Esters. JOURNAL OF MACROMOLECULAR SCIENCE PART A-PURE AND APPLIED CHEMISTRY 2005. [DOI: 10.1080/10601320500229061] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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1306
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de Carvalho CCCR, da Fonseca MMR. Biotransformation of terpenes. Biotechnol Adv 2005; 24:134-42. [PMID: 16169182 DOI: 10.1016/j.biotechadv.2005.08.004] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2005] [Accepted: 08/13/2005] [Indexed: 10/25/2022]
Abstract
The main application of terpenes as fragrances and flavors depends on the absolute configuration of the compounds because enantiomers present different organoleptic properties. Biotransformations allow the production of regio- and stereoselective compounds under mild conditions. These products may be labeled as "natural". Commercially useful chemical building-blocks and pharmaceutical stereo isomers can also be produced by bioconversion of terpenes. Enzymes and extracts from bacteria, cyanobacteria, yeasts, microalgae, fungi, plants, and animal cells have been used for the production and/or bioconversion of terpenes. In addition, whole cell catalysis has also been used. A variety of media and reactors have been assessed for these biotransformations and have produced encouraging results, as discussed in this review.
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Affiliation(s)
- Carla C C R de Carvalho
- Centro de Engenharia Biológica e Química, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Lisbon, Portugal.
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1307
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Habulin M, Primožič M, Knez Ž. Enzymatic Reactions in High-Pressure Membrane Reactors. Ind Eng Chem Res 2005. [DOI: 10.1021/ie0502685] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Maja Habulin
- Laboratory for Separation Processes, Faculty of Chemistry and Chemical Engineering, University of Maribor, Smetanova 17, SI-2000 Maribor, Slovenia
| | - Mateja Primožič
- Laboratory for Separation Processes, Faculty of Chemistry and Chemical Engineering, University of Maribor, Smetanova 17, SI-2000 Maribor, Slovenia
| | - Željko Knez
- Laboratory for Separation Processes, Faculty of Chemistry and Chemical Engineering, University of Maribor, Smetanova 17, SI-2000 Maribor, Slovenia
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1308
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Kreiner M, Parker MC. Protein-coated Microcrystals for use in Organic Solvents: Application to Oxidoreductases. Biotechnol Lett 2005; 27:1571-7. [PMID: 16245176 DOI: 10.1007/s10529-005-1800-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2005] [Revised: 07/27/2005] [Accepted: 07/28/2005] [Indexed: 11/24/2022]
Abstract
Protein-coated microcrystals (PCMC), a biocatalyst preparation previously demonstrated to display substantially increased transesterification activity of proteases and lipases in organic solvents when compared to their as received counterparts [Kreiner M, Moore BD, Parker MC (2001) Chem. Commun. 12:1096--1097], was applied to oxidoreductases. Horse liver alcohol dehydrogenase (HLADH), catalase (CAT), soybean peroxidase and horseradish peroxidase were immobilised onto K(2)SO(4) crystals and dehydrated in a 1-step process, resulting in PCMC. These PCMC preparations showed enhanced activity in different organic solvents in most types of reactions tested. The highest activation was observed with HLADH (50-fold as active as enzyme as received) and CAT (25-fold).
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Affiliation(s)
- Michaela Kreiner
- Department of Chemistry, University of Glasgow, Joseph Black Building, G12 8QQ, Glasgow, UK
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1309
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Abstract
We report a family of biocompatible ionic liquids (ILs) which are able to dissolve significant amounts of proteins such as cytochrome c and in which ATR-FTIR spectroscopy results show retention of secondary structure to extreme temperatures.
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Affiliation(s)
- Kyoko Fujita
- School of Chemistry, Monash University, Clayton, VIC, Australia
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1310
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Eibes G, Lú-Chau T, Feijoo G, Moreira M, Lema J. Complete degradation of anthracene by Manganese Peroxidase in organic solvent mixtures. Enzyme Microb Technol 2005. [DOI: 10.1016/j.enzmictec.2004.02.010] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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1311
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Kang IJ, Pfromm PH, Rezac ME. Real time measurement and control of thermodynamic water activities for enzymatic catalysis in hexane. J Biotechnol 2005; 119:147-54. [PMID: 15941606 DOI: 10.1016/j.jbiotec.2005.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2004] [Revised: 04/06/2005] [Accepted: 04/12/2005] [Indexed: 11/23/2022]
Abstract
The esterification reaction of geraniol with acetic acid catalyzed by immobilized Candida antarctica lipase B was studied in hexane using a pervaporation-assisted batch reactor. The effect of thermodynamic water activity (a(w)) on the initial reaction rate was investigated at a(w) ranging from 0.02 to 1.0. The a(w) was monitored on-line in real time. a(w) was actively controlled throughout the reaction by using highly water-selective membrane pervaporation. This novel combination of a(w) sensing and control eliminates changes in a(w) during the reaction even in the initial phase of relatively rapid water release during an esterification. No chemicals are introduced for a(w) control, and no purge gases or liquids are needed. A maximum in the initial reaction rate was found approximately at a(w)=0.1. The initial reaction rate declined quickly at higher a(w), and dropped precipitously at lower a(w).
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Affiliation(s)
- I J Kang
- Kansas State University, Department of Chemical Engineering, 105 Durland Hall, Manhattan, KS 66506-5102, USA
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1312
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Vidinha P, Augusto V, Almeida M, Fonseca I, Fidalgo A, Ilharco L, Cabral JMS, Barreiros S. Sol-gel encapsulation: an efficient and versatile immobilization technique for cutinase in non-aqueous media. J Biotechnol 2005; 121:23-33. [PMID: 16095741 DOI: 10.1016/j.jbiotec.2005.06.018] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2005] [Revised: 06/22/2005] [Accepted: 06/27/2005] [Indexed: 10/25/2022]
Abstract
Cutinase from Fusarium solani pisi was encapsulated in sol-gel matrices prepared with a combination of alkyl-alkoxysilane precursors of different chain-lengths. The specific activity of cutinase in a model transesterification reaction at fixed water activity in n-hexane was highest for the precursor combination tetramethoxysilane/n-butyltrimetoxysilane (TMOS/BTMS) in a 1:5 ratio, lower and higher chain lengths of the mono-alkylated precursor or decreasing proportions of the latter relative to TMOS leading to lower enzyme activity. Results obtained using combinations of three precursors confirmed the beneficial effect of the presence of BTMS in the preparations. Scanning electron microscopy of the 1:5 TMOS/n-alkylTMS gels showed a direct correlation between the macropore dimensions and the alkyl chain length of the alkylated precursor and revealed that TMOS/n-octylTMS gels suffered extensive pore collapse during the drying process. The specific activity of TMOS/BTMS sol-gel entrapped cutinase was similar to that exhibited by the enzyme immobilized by adsorption on zeolite NaY. However, the incorporation of different additives (zeolites, silica, Biogel, grinded sol-gel, etc.) having in common the capability to react with residual silanol groups of the sol-gel matrix brought about remarkable enhancements of cutinase activity, despite the fact that the global porosity of the gels did not change. The behavior of the gels in supercritical CO 2 (sc-CO 2) paralleled that exhibited in n-hexane, although cutinase activity was ca. one order of magnitude lower (i.e. sol-gel encapsulation did not prevent the deleterious effect of CO 2. The impact that functionalization of some of the additives had on cutinase activity indicates that the enzyme/matrix interactions must play an important role. Some of the best additives from the standpoint of enzyme activity were also the best from the standpoint of its operational stability (ca. 80% retention of enzyme activity at the tenth reutilization cycle). None of the additives that proved effective for cutinase could improve the catalytic activity of sol-gel encapsulated Pseudomonas cepacia lipase.
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Affiliation(s)
- Pedro Vidinha
- REQUIMTE/CQFB, Departamento de Química, FCT, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
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1313
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Garcia S, Vidinha P, Arvana H, Gomes da Silva MD, Ferreira MO, Cabral JM, Macedo EA, Harper N, Barreiros S. Cutinase activity in supercritical and organic media: water activity, solvation and acid–base effects. J Supercrit Fluids 2005. [DOI: 10.1016/j.supflu.2004.10.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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1314
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Verkerk UH, Kebarle P. Ion-ion and ion-molecule reactions at the surface of proteins produced by nanospray. Information on the number of acidic residues and control of the number of ionized acidic and basic residues. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2005; 16:1325-41. [PMID: 15979326 DOI: 10.1016/j.jasms.2005.03.018] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2004] [Revised: 02/14/2005] [Accepted: 03/16/2005] [Indexed: 05/03/2023]
Abstract
Mass Spectra of charge states of folded proteins were obtained with nanospray and aqueous solution containing 20 microM the protein (ubiquitin, cytochrome c, lysozyme) and one of the NaA salts NaCl, NaI, NaAc (acetate) (1-10 mM). At very low collision activated decomposition (CAD), the mass spectra of a protein with charge z exhibited a replacement of zH+ with zNa+ and also multiple adducts of NaA. Higher CAD converts the NaA adduct peaks to Na minus H peaks. These must be due to loss of HA where the H was provided by the protein. The degree of HA loss with increasing CAD followed the order I < Cl < Ac. Significantly, the intensity of the ions with n (Na minus H) adducts showed a downward break past an n(MAX) which is equal to the number of acidic residues of the protein plus the charge of the protein. All the observations could be rationalized within the framework of the electrospray mechanism and the charge residue model, which predict that due to extensive evaporation of solvent, the solutes will reach very high concentrations in the final charged droplets. At such high concentrations, positive ions such as Na+, NH4+ form ion pairs with ionized acidic residues and the negative A- form ion pairs with ionized basic residues of the protein. Adducts of Na+, and NaA to backbone amide groups occur also. This reaction mechanism fits all the experimental observations and provides predictions that the number of acidic and basic groups at the surface of the gaseous protein that remain ionized can be controlled by the absence or presence of additives to the solution.
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Affiliation(s)
- Udo H Verkerk
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
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1315
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Fleminger G, Yaron T, Eisenstein M, Bar-Nun A. The structure and synthetic capabilities of a catalytic peptide formed by substrate-directed mechanism--implications to prebiotic catalysis. ORIGINS LIFE EVOL B 2005; 35:369-82. [PMID: 16228649 DOI: 10.1007/s11084-005-4084-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2004] [Accepted: 08/20/2004] [Indexed: 10/25/2022]
Abstract
Previously, we have shown that a small substrate may serve as a template in the formation of a specific catalytic peptide, a phenomenon which might have had a major role in prebiotic synthesis of peptide catalysts. This was demonstrated experimentally by the formation of a catalytic metallo-dipeptide, Cys2-Fe2+, around o-nitrophenyl beta-D-galactopyranoside (ONPG), by dicyandiamide (DCDA)-assisted condensation under aqueous conditions. This dipeptide was capable of hydrolyzing ONPG at a specific activity lower only 1000 fold than that of beta galactosidase. In the present paper we use molecular modeling techniques to elucidate the structure of this catalyst and its complex with the substrate and propose a putative mechanism for the catalyst formation and its mode of action as a "mini enzyme". This model suggests that interaction of Fe2+ ion with ONPG oxygens and with two cysteine SH groups promotes the specific formation of the Cys2-Fe2+ catalyst. Similarly, the interaction of the catalyst with ONPG is mediated by its Fe2+ with the substrate oxygens, leading to its hydrolysis. In addition, immobilized forms of the catalyst were synthesized on two carriers--Eupergit C and amino glass beads. These preparations were capable of catalyzing the formation of ONPG from beta-D-galactose and o-nitrophenol (ONP) under anhydrous conditions. The ability of the catalyst to synthesize the substrate that mediates its own formation creates an autocatalytic cycle where ONPG catalyzes the formation of a catalyst which, in turn, catalyzes ONPG formation. Such autocatalytic cycle can only operate by switching between high and low water activity conditions, such as in tidal pools cycling between wet and dry environments. Implications of the substrate-dependent formation of catalytically active peptides to prebiotic processes are discussed.
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Affiliation(s)
- Gideon Fleminger
- Department of Molecular Microbiology and Biotechnology, George Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
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1316
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Wang N, Wu Q, Wu WB, Quan J, Lin XF. Lipase-catalyzed regioselective synthesis of lipophilic inosine ester derivatives. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.molcatb.2005.04.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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1317
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Lavandera I, García J, Fernández S, Ferrero M, Gotor V, Sanghvi YS. Enzymatic Regioselective Levulinylation of 2′‐Deoxyribonucleosides and 2′‐
O
‐Methylribonucleosides. ACTA ACUST UNITED AC 2005; Chapter 2:Unit 2.11. [DOI: 10.1002/0471142700.nc0211s21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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1318
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Limbach M. ‘Five at One Stroke’: Proline and Small Peptides in the Stereoselectivede novo Synthesis and Enantiotopic Functionalization of Carbohydrates. Chem Biodivers 2005; 2:825-36. [PMID: 17193175 DOI: 10.1002/cbdv.200590061] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Asymmetric catalysis with the simple amino acid proline (so called 'enamine catalysis') arrested big attention in the last few years since the re-discovery of the Hajos-Parrish-Eder-Sauer-Wiechert reaction. After basic mechanistic studies, probing scope and limitations of the catalyst and the corresponding reactions, this concept has now emerged to a state where it is applied to the assembly of up to five stereogenic centers of carbohydrates, not really 'at one stroke', but in only two simple synthetic operations. Beyond, it is not only possible to build up complicated natural products elegantly, but also to address selectively the similar functional groups of carbohydrates by small peptidic catalysts. This short review covers the recent developments of organocatalysis in both fields, with special emphasis on the asymmetric assembly and selective derivatization of carbohydrates.
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Affiliation(s)
- Michael Limbach
- Laboratorium für Organische Chemie, Department Chemie und Angewandte Biowissenschaften, Eidgenössische Technische Hochschule, ETH Hönggerberg, HCI, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich.
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1319
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1320
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Würges K, Pfromm PH, Rezac ME, Czermak P. Activation of subtilisin Carlsberg in hexane by lyophilization in the presence of fumed silica. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.molcatb.2005.04.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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1321
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Mahiuddin S, Renoncourt A, Bauduin P, Touraud D, Kunz W. Horseradish peroxidase activity in a reverse catanionic microemulsion. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:5259-62. [PMID: 15924447 DOI: 10.1021/la047161r] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
In this paper we present the first results of enzymatic activities in a reverse microemulsion medium based on a mixture of an anionic and a cationic surfactant, called catanionic microemulsion. The studied system is composed of sodium dodecyl sulfate (SDS)/dodecyltrimethylammonium bromide (DTAB)/n-hexanol/citrate buffer/n-dodecane, with high SDS/(SDS + DTAB) weight fractions. It turns out that the results are similar to those obtained in classical reverse microemulsions, except that the presence of DTAB exerts an inhibiting effect on the enzyme. Nevertheless, enzymatic superactivities are found even at a DTAB to total surfactant ratio of 15%, corresponding to 3% weight fraction of cationic surfactant in the microemulsion. The influence of pH and hexanol content on the enzymatic activities is also studied.
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Affiliation(s)
- Sekh Mahiuddin
- Material Science Division, Regional Research Laboratory, Jorhat-785 006, Assam, India
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1322
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A new way to conduct enzymatic synthesis in an active membrane using ionic liquids as catalyst support. Catal Today 2005. [DOI: 10.1016/j.cattod.2005.03.039] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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1323
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1324
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Intra A, Nicotra S, Riva S, Danieli B. Significant and Unexpected Solvent Influence on the Selectivity of Laccase-Catalyzed Coupling of Tetrahydro-2-naphthol Derivatives. Adv Synth Catal 2005. [DOI: 10.1002/adsc.200505043] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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1325
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Sirotkin VA. Effect of dioxane on the structure and hydration–dehydration of α-chymotrypsin as measured by FTIR spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2005; 1750:17-29. [PMID: 15882959 DOI: 10.1016/j.bbapap.2005.02.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2004] [Revised: 02/09/2005] [Accepted: 02/22/2005] [Indexed: 10/25/2022]
Abstract
A new experimental approach based on FTIR spectroscopic measurements was proposed to study simultaneously the adsorption/desorption of water and organic solvent on solid enzyme and corresponding changes in the enzyme secondary structure in the water activity range from 0 to 1.0 at 25 degrees C. The effect of dioxane on the hydration/dehydration and structure of bovine pancreatic alpha-chymotrypsin (CT) was characterized by means of this approach. Dioxane sorption exhibits pronounced hysteresis. No sorbed dioxane was observed at low water activities (a(w)<0.5) during hydration. At a(w) about 0.5, a sharp increase in the amount of sorbed dioxane was observed. Dioxane sorption isotherm obtained during dehydration resembles a smooth curve. In this case, CT binds about 150 mol dioxane/mol enzyme at the lowest water activities. Three different effects of dioxane on the water binding by the initially dried CT were observed. At a(w)<0.5, water adsorption is similar in the presence and absence of dioxane. It was concluded that the presence of dioxane has little effect on the interaction between enzyme and tightly bound water at low a(w). At a(w)>0.5, dioxane increases the amount of water bound by CT during hydration. This behavior was interpreted as a dioxane-assisted effect on water binding. Upon dehydration at low water activities, dioxane decreases the water content at a given a(w). This behavior suggests that the suppression in the uptake of water during dehydration may be due to a competition for water-binding sites on chymotrypsin by dioxane. Changes in the secondary structure of CT were determined from infrared spectra by analyzing the structure of amide I band. Dioxane induced a strong band at 1628 cm(-1) that was assigned to the intermolecular beta-sheet aggregation. Changes in the intensity of the 1628 cm(-1) band agree well with changes in the dioxane sorption by CT. An explanation of the dioxane effect on the CT hydration and structure was provided on the basis of hypothesis on water-assisted disruption of polar contacts in the solid enzyme. The reported results demonstrate that the hydration and structure of alpha-chymotrypsin depend markedly on how enzyme has been hydrated - whether in the presence or in the absence of organic solvent. A qualitative model was proposed to classify the effect of hydration history on the enzyme activity-a(w) profiles.
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Affiliation(s)
- Vladimir A Sirotkin
- Kazan State University, Butlerov Institute of Chemistry, Kremlevskaya str., 18, Kazan, 420008, Russia.
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1326
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Rahman RNZRA, Baharum SN, Basri M, Salleh AB. High-yield purification of an organic solvent-tolerant lipase from Pseudomonas sp. strain S5. Anal Biochem 2005; 341:267-74. [PMID: 15907872 DOI: 10.1016/j.ab.2005.03.006] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2004] [Indexed: 11/23/2022]
Abstract
An organic solvent-tolerant S5 lipase was purified by affinity chromatography and anion exchange chromatography. The molecular mass of the lipase was estimated to be 60 kDa with 387 purification fold. The optimal temperature and pH were 45 degrees C and 9.0, respectively. The purified lipase was stable at 45 degrees C and pH 6-9. It exhibited the highest stability in the presence of various organic solvents such as n-dodecane, 1-pentanol, and toluene. Ca2+ and Mg2+ stimulated lipase activity, whereas EDTA had no effect on its activity. The S5 lipase exhibited the highest activity in the presence of palm oil as a natural oil and triolein as a synthetic triglyceride. It showed random positional specificity on the thin-layer chromatography.
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1327
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1328
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Micaelo NM, Teixeira VH, Baptista AM, Soares CM. Water dependent properties of cutinase in nonaqueous solvents: a computational study of enantioselectivity. Biophys J 2005; 89:999-1008. [PMID: 15923226 PMCID: PMC1366647 DOI: 10.1529/biophysj.105.063297] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The catalytic properties of enzymes in nonaqueous solvents are known to be dependent on the nature of the solvent. Here we present a molecular modeling study of the enantioselective properties of the enzyme cutinase in hexane under varying hydration conditions. Previous simulation studies have shown that for this model enzyme in hexane, the structural and dynamical properties are affected by the amount of water associated with the protein, being more similar to the aqueous simulation at 5-10% of water content. The implications of the hydration levels on the enzyme resolution of (R,S)-1-phenylethanol and (R,S)-2-phenyl-1-propanol are investigated using free energy calculations of the tetrahedral intermediate (TI) model. With this model system we show that the enzyme enantioselective properties are under the control of the amount of water present in the organic media. Maximum enantioselectivity is achieved at 10% water content. The stabilizing effects of the catalytic histidine on the TI are evaluated at different water contents and shown to be correlated. The correlation between the amount of water present in the media and the structural, dynamical, and thermodynamic properties of the enzyme are examined as well as the active site discriminative power.
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Affiliation(s)
- Nuno M Micaelo
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
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1329
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Affiliation(s)
- J Jegan Roy
- Biochemical Processing Section, Regional Research Laboratory (CSIR), Trivandrum 695 019, India
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1330
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Anarbaev RO, Khodyreva SN, Zakharenko AL, Rechkunova NI, Lavrik OI. DNA polymerase activity in water-structured and confined environment of reverse micelles. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.molcatb.2005.01.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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1331
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Louwrier A, van der Valk A. Thermally reversible inactivation of Taq polymerase in an organic solvent for application in hot start PCR. Enzyme Microb Technol 2005. [DOI: 10.1016/j.enzmictec.2005.01.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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1332
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Kawanami Y, Itoh K. Highly Enantioselective Lipase-catalyzed Kinetic Resolution of 2-Silyloxy-1-propanol. CHEM LETT 2005. [DOI: 10.1246/cl.2005.682] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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1333
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Sieber SA, Marahiel MA. Molecular mechanisms underlying nonribosomal peptide synthesis: approaches to new antibiotics. Chem Rev 2005; 105:715-38. [PMID: 15700962 DOI: 10.1021/cr0301191] [Citation(s) in RCA: 442] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Stephan A Sieber
- Philipps-Universität Marburg, Fachbereich Chemie/Biochemie, Hans-Meerwein-Strasse, 35032 Marburg, Germany
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1334
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1336
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Ternström T, Svendsen A, Akke M, Adlercreutz P. Unfolding and inactivation of cutinases by AOT and guanidine hydrochloride. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2005; 1748:74-83. [PMID: 15752695 DOI: 10.1016/j.bbapap.2004.12.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2004] [Revised: 12/08/2004] [Accepted: 12/15/2004] [Indexed: 11/17/2022]
Abstract
We present a comparative analysis of the unfolding and inactivation of three cutinases in the presence of guanidine hydrochloride (GdnHCl) and bis(2-ethylhexyl) sodium sulfosuccinate (AOT). Previous investigations have focused on the cutinase from Fusarium solani pisi (FsC). In addition to FsC, the present study includes the cutinase from Humicola insolens (HiC) and a mutant variant of HiC (muHiC) with increased activity and decreased surfactant sensitivity. Equilibrium and time-resolved denaturation by AOT were studied in aqueous solution and reverse micelles, and were compared with GdnHCl denaturation. The far-UV CD and fluorescence denaturation profiles obtained in the aqueous solutions of the two denaturants coincide for all three cutinases, indicating that unfolding is a co-operative two-state process under these conditions. In reverse micelles, the cutinases unfold with mono-exponential rates, again indicating a two-state process. The free energy of denaturation in water was calculated by linear extrapolation of equilibrium data, yielding very similar values for the three cutinases with averages of -11.6 kcal mol(-1) and -2.6 kcal mol(-1) for GdnHCl and AOT, respectively. Hence, the AOT denatured state (D(AOT)) is less destabilised than the GdnHCl denatured state (D(GdnHCl)), relative to the native state in water. Far-UV CD spectroscopy revealed that D(AOT) retains some secondary structure, while D(GdnHCl) is essentially unstructured. Similarly, fluorescence data suggest that D(AOT) is more compact than D(GdnHCl). Activity measurements reveal that both D(AOT) and D(GdnHCl) are practically inactive (catalytic activity <1% of that of the native enzyme). The fluorescence spectrum of D(AOT) in reverse micelles did not differ significantly from that observed in aqueous AOT. NMR studies of D(AOT) in reverse micelles indicated that the structure is characteristic of a molten globule, consistent with the CD and fluorescence data.
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Affiliation(s)
- Tomas Ternström
- Department of Biochemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
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1337
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Fujii R, Nakagawa Y, Hiratake J, Sogabe A, Sakata K. Directed evolution of Pseudomonas aeruginosa lipase for improved amide-hydrolyzing activity. Protein Eng Des Sel 2005; 18:93-101. [PMID: 15788423 DOI: 10.1093/protein/gzi001] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A lipase from Pseudomonas aeruginosa was subjected to directed molecular evolution for increased amide-hydrolyzing (amidase) activity. A single round of random mutagenesis followed by screening for hydrolytic activity for oleoyl 2-naphthylamide as compared with that for oleoyl 2-naphthyl ester identified five mutants with 1.7-2.0-fold increased relative amidase activities. Three mutational sites (F207S, A213D and F265L) were found to affect the amidase/esterase activity ratios. The combination of these mutations further improved the amidase activity. Active-site titration using a fluorescent phosphonic acid ester allowed the molecular activities for the amide and the ester to be determined for each mutant without purification of the lipase. A double mutant F207S/A213D gave the highest molecular activity of 1.1 min(-1) for the amide, corresponding to a 2-fold increase compared with that of the wild-type lipase. A structural model of the lipase indicated that the mutations occurred at the sites near the surface and remote from the catalytic triad, but close to the calcium binding site. This study is a first step towards understanding why lipases do not hydrolyze amides despite the similarities to serine proteases in the active site structure and the reaction mechanism and towards the preparation of a general acyl transfer catalyst for the biotransformation of amides.
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Affiliation(s)
- Ryota Fujii
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan and Tsuruga Institute of Biotechnology, Toyobo Co., Ltd, 10-24 Toyo-Cho, Tsuruga, Fukui 914-0047, Japan
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García-Urdiales E, Alfonso I, Gotor V. Enantioselective enzymatic desymmetrizations in organic synthesis. Chem Rev 2005; 105:313-54. [PMID: 15720156 DOI: 10.1021/cr040640a] [Citation(s) in RCA: 393] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Eduardo García-Urdiales
- Departamento de Química Orgánica e Inorgánica, Facultad de Química, Universidad de Oviedo, Julián Clavería, 8, 33071 Oviedo, Spain
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1339
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Bacheva AV, Belyaeva AV, Lysogorskaya EN, Oksenoit ES, Lozinsky VI, Filippova IY. Biocatalytic properties of native and immobilized subtilisin 72 in aqueous-organic and low water media. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.molcatb.2004.12.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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1340
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Zhou R, Xu JH. Enantioselective synthesis of (S)-α-cyano-3-phenoxybenzyl alcohol by lipase-catalyzed alcoholysis of racemic ester in organic medium. Biochem Eng J 2005. [DOI: 10.1016/j.bej.2004.10.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
Protein and peptide delivery has been a challenge due to their limited stability during preparation of formulation, storage and in vitro and in vivo release. These biopolymers have traditionally been administered via intramuscular or subcutaneous routes. Recent efforts have been made to develop formulations for non-invasive routes of administration, including oral, intranasal, transdermal and transmucosal delivery. Despite these efforts, invasive delivery remains the main method of administering peptide and protein drugs. This review focuses on recent developments in injectable, polymeric controlled-release formulations, with an emphasis on hydrogels and particulate systems.
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Affiliation(s)
- Rajendra Pawar
- The Hebrew University of Jerusalem, School of Pharmacy-Faculty of Medicine, Department of Medicinal Chemistry and Natural Products, Jerusalem 91120, Israel
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Yang L, Dordick JS, Garde S. Hydration of enzyme in nonaqueous media is consistent with solvent dependence of its activity. Biophys J 2005; 87:812-21. [PMID: 15298890 PMCID: PMC1304491 DOI: 10.1529/biophysj.104.041269] [Citation(s) in RCA: 191] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Water plays an important role in enzyme structure and function in aqueous media. That role becomes even more important when one focuses on enzymes in low water media. Here we present results from molecular dynamics simulations of surfactant-solubilized subtilisin BPN' in three organic solvents (octane, tetrahydrofuran, and acetonitrile) and in pure water. Trajectories from simulations are analyzed with a focus on enzyme structure, flexibility, and the details of enzyme hydration. The overall enzyme and backbone structures, as well as individual residue flexibility, do not show significant differences between water and the three organic solvents over a timescale of several nanoseconds currently accessible to large-scale molecular dynamics simulations. The key factor that distinguishes molecular-level details in different media is the partitioning of hydration water between the enzyme and the bulk solvent. The enzyme surface and the active site region are well hydrated in aqueous medium, whereas with increasing polarity of the organic solvent (octane --> tetrahydrofuran --> acetonitrile) the hydration water is stripped from the enzyme surface. Water stripping is accompanied by the penetration of tetrahydrofuran and acetonitrile molecules into crevices on the enzyme surface and especially into the active site. More polar organic solvents (tetrahydrofuran and acetonitrile) replace mobile and weakly bound water molecules in the active site and leave primarily the tightly bound water in that region. In contrast, the lack of water stripping in octane allows efficient hydration of the active site uniformly by mobile and weakly bound water and some structural water similar to that in aqueous solution. These differences in the active site hydration are consistent with the inverse dependence of enzymatic activity on organic solvent polarity and indicate that the behavior of hydration water on the enzyme surface and in the active site is an important determinant of biological function especially in low water media.
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Affiliation(s)
- Lu Yang
- Department of Chemical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
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1343
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Abstract
A high-density coding system is essential to allow cells to communicate efficiently and swiftly through complex surface interactions. All the structural requirements for forming a wide array of signals with a system of minimal size are met by oligomers of carbohydrates. These molecules surpass amino acids and nucleotides by far in information-storing capacity and serve as ligands in biorecognition processes for the transfer of information. The results of work aiming to reveal the intricate ways in which oligosaccharide determinants of cellular glycoconjugates interact with tissue lectins and thereby trigger multifarious cellular responses (e.g. in adhesion or growth regulation) are teaching amazing lessons about the range of finely tuned activities involved. The ability of enzymes to generate an enormous diversity of biochemical signals is matched by receptor proteins (lectins), which are equally elaborate. The multiformity of lectins ensures accurate signal decoding and transmission. The exquisite refinement of both sides of the protein-carbohydrate recognition system turns the structural complexity of glycans--a demanding but essentially mastered problem for analytical chemistry--into a biochemical virtue. The emerging medical importance of protein-carbohydrate recognition, for example in combating infection and the spread of tumors or in targeting drugs, also explains why this interaction system is no longer below industrial radarscopes. Our review sketches the concept of the sugar code, with a solid description of the historical background. We also place emphasis on a distinctive feature of the code, that is, the potential of a carbohydrate ligand to adopt various defined shapes, each with its own particular ligand properties (differential conformer selection). Proper consideration of the structure and shape of the ligand enables us to envision the chemical design of potent binding partners for a target (in lectin-mediated drug delivery) or ways to block lectins of medical importance (in infection, tumor spread, or inflammation).
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Affiliation(s)
- Hans-Joachim Gabius
- Institut für Physiologische Chemie, Tierärztliche Fakultät, Ludwig-Maximilians-Universität, Veterinärstrasse 13, 80539 Munich, Germany.
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Zhang TZ, Yang LR, Zhu ZQ. Optimization of technological conditions for one-pot synthesis of (S)-alpha-cyano-3-phenoxybenzyl acetate in organic media. J Zhejiang Univ Sci B 2005; 6:175-81. [PMID: 15682501 PMCID: PMC1389718 DOI: 10.1631/jzus.2005.b0175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Optically active form of alpha-cyano-3-phenoxybenzyl (CPB) alcohol, building block of pyrethroid insecticides, was synthesized as its acetate by the combination of anion-exchange resin (D301)-catalyzed transcyanation between m-phenoxybenzaldehyde (m-PBA) and acetone cyanohydrin (AC), and lipase (from Alcaligenes sp.)-catalyzed enantioselective transesterification of the resulting cyanohydrin with vinyl acetate. Through optimizing technological conditions, the catalyzing efficiency was improved considerably compared to methods previously reported. Concentrations of CPB acetate were determined by gas chromatograph. The enantio excess (e.e.) values of CPB acetate were measured by NMR (nuclear magnetic resonance) method. Effects of solvents and temperatures on this reaction were studied. Cyclohexane was shown to be the best solvent among the three tested solvents. 55 degrees C was the optimal temperature for higher degree of conversion. External diffusion limitation was excluded by raising the rotational speed to 220 r/min. However, internal diffusion could not be ignored, since the catalyst (lipase) was an immobilized enzyme and its particle dimension was not made small enough. The reaction rate was substantially accelerated when the reactant (m-PBA) concentration was as high as 249 mmol/L, but decreased when the initial concentration of m-PBA reached to 277 mmol/L. It was also found that the catalyzing capability of recovered lipase was high enough to use several batches. Study of the mole ratio of AC to m-PBA showed that 2:1 was the best choice. The strategy of adding base catalyst D301 was found to be an important factor in improving the degree of conversion of the reaction from 20% to 80%. The highest degree of conversion of the reaction has reached up to 80%.
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Affiliation(s)
- Ting-zhou Zhang
- School of Material & Chemical Engineering, Zhejiang University, Hangzhou 310027, China
- School of Food Science, Biotechnology & Environmental Engineering, Zhejiang Gongshang University, Hangzhou 310035, China
- †E-mail:;
| | - Li-rong Yang
- School of Material & Chemical Engineering, Zhejiang University, Hangzhou 310027, China
- †E-mail:;
| | - Zi-qiang Zhu
- School of Material & Chemical Engineering, Zhejiang University, Hangzhou 310027, China
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1345
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O'Reilly NJ, Magner E. Electrochemistry of cytochrome C in aqueous and mixed solvent solutions: thermodynamics, kinetics, and the effect of solvent dielectric constant. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:1009-1014. [PMID: 15667182 DOI: 10.1021/la048796t] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The solvent dielectric constant is considered an important factor in determining the redox potential of the heme-containing protein cytochrome c in solution. In this study, we investigate the electrochemical response of cytochrome c in aqueous/organic solvent mixtures (100% aqueous buffer, 30% acetonitrile, 40% dimethyl sulfoxide, and 50% methanol), reporting the redox potential (E degrees'), enthalpy, and entropy of reduction. The temperature dependence of the solvent dielectric constant (epsilon) was also measured. The results show that epsilon alone cannot regulate the E degrees' of cytochrome c in mixed solvent systems. The implications of the temperature dependence of epsilon on the validity of the thermodynamic data are also discussed. The effect of solvent and temperature on the electron-transfer rate constant, k(s), was determined in each solvent mixture. A substantial increase in the activation energy for electron transfer was observed in 40% DMSO.
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Affiliation(s)
- Niall J O'Reilly
- Department of Chemical and Environmental Sciences and Materials and Surface Science Institute, University of Limerick, Castletroy, Limerick, Ireland
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1346
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D'Antona N, El-Idrissi M, Ittobane N, Nicolosi G. Enzymatic procedures in the preparation of regioprotected d-fructose derivatives. Carbohydr Res 2005; 340:319-23. [PMID: 15639253 DOI: 10.1016/j.carres.2004.11.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2004] [Revised: 11/05/2004] [Accepted: 11/06/2004] [Indexed: 10/26/2022]
Abstract
A combination of different lipases from Pseudomonas cepacia, Candida antarctica B, Candida rugosa and Mucor miehei, aided the regioesterification of the free fructose allowing the synthesis of 1,6-di-O-acetyl-D-fructofuranose, 1,4,6-tri-O-acetyl-D-fructofuranose, 1,6-di-O-acetyl-4-O-benzoyl-D-fructofuranose and 1,6-di-O-benzoyl-D-fructofuranose. Using C. antarctica B and C. rugosa lipases the alcoholysis of fructose peracetate (alpha, beta-form) has furnished 1,2,3,4-tetra-O-acetyl-alpha-D-fructofuranose and 2,3,4,6-tetra-O-acetyl-beta-D-fructofuranose. 1,4,6-Tri-O-acetyl-D-fructofuranose was successfully employed to produce a rare ketohexose, namely D-psicose.
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Affiliation(s)
- Nicola D'Antona
- CNR Istituto Chimica Biomolecolare, Sezione CT, via del santuario 110, 95028 Valverde CT, Italy
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1347
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Fragrance release from the surface of branched poly (amide)s. Molecules 2005; 10:81-97. [PMID: 18007278 PMCID: PMC6147641 DOI: 10.3390/10010081] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2004] [Accepted: 06/29/2005] [Indexed: 11/17/2022] Open
Abstract
Enzymes are powerful tools in organic synthesis that are able to catalyse a wide variety of selective chemical transformations under mild and environmentally friendly conditions. Enzymes such as the lipases have also found applications in the synthesis and degradation of polymeric materials. However, the use of these natural catalysts in the synthesis and the post-synthetic modification of dendrimers and hyperbranched molecules is an application of chemistry yet to be explored extensively. In this study the use of two hydrolytic enzymes, a lipase from Candida cylindracea and a cutinase from Fusarium solani pisii, were investigated in the selective cleavage of ester groups situated on the peripheral layer of two families of branched polyamides. These branched polyamides were conjugated to simple fragrances citronellol and L-menthol via ester linkages. Hydrolysis of the ester linkage between the fragrances and the branched polyamide support was carried out in aqueous buffered systems at slightly basic pH values under the optimum operative conditions for the enzymes used. These preliminary qualitative investigations revealed that partial cleavage of the ester functionalities from the branched polyamide support had occurred. However, the ability of the enzymes to interact with the substrates decreased considerably as the branching density, the rigidity of the structure and the bulkiness of the polyamide-fragrance conjugates increased.
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1348
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Kreiner M, Parker MC. High-activity biocatalysts in organic media: solid-state buffers as the immobilisation matrix for protein-coated microcrystals. Biotechnol Bioeng 2005; 87:24-33. [PMID: 15211485 DOI: 10.1002/bit.20101] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Recently, we reported a new high-activity biocatalyst for use in organic media termed protein-coated microcrystals (PCMC) (Kreiner et al. [2001] Chem Commun 12:1096-1097). These novel particles consist of water-soluble micron-sized crystalline particles coated with the given biocatalyst(s) and are prepared in a one-step rapid dehydration process. In this study we extended the choice of immobilisation matrix from a simple inorganic salt, K(2)SO(4), to other compounds, both inorganic and zwitterionic, that act as solid-state buffers for biocatalysis in organic media. The catalytic activity of serine proteases subtilisin Carlsberg (SC) and alpha-chymotrypsin (CT) were significantly increased when coated onto the surface of solid-state buffers, as measured in acetonitrile/1wt% H(2)O. SC-PCMC with both organic and inorganic buffer carriers (Na-AMPSO, Na(2)CO(3), and NaHCO(3)) showed a 3-fold greater activity than that observed when using the unbuffered system (PCMC-SC/K(2)SO(4)). In comparison with freeze-dried preparations, this represents an approximately 3,000-fold increase in catalytic activity. Importantly, there is no improvement in catalytic activity upon external addition of any of the solid-state buffers to the reaction mixture. When acting in a solid-state buffer capacity, good buffering capacity was observed with SC-PCMC (3 wt% protein loading) prepared from a 1:1 mixture of AMPSO and AMPSO-Na. Alternatively, increasing the amount of solid-state buffer in the system allows improvement of the buffering. This can be achieved either by decreasing the protein loading of the SC/Na-AMPSO-PCMC or by addition of further external solid-state buffer to the reaction mixture. The catalytic activity of lipase-PCMC prepared from solid-state buffers was found less responsive to immobilisation.
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Affiliation(s)
- Michaela Kreiner
- Department of Chemistry, University of Glasgow, Joseph Black Building, Glasgow G12 8QQ, Scotland, UK.
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1349
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Ueji SI, Mori SI, Yumoto H, Hiroshima N, Ebara Y. Lyophilization of Lipase Together with Ionic Compounds Generates Highly Enantioselective and Solvent-sensitive Lipase in Organic Solvents. CHEM LETT 2005. [DOI: 10.1246/cl.2005.110] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Silva C, Matamá T, Guebitz GM, Cavaco-Paulo A. Influence of organic solvents on cutinase stability and accessibility to polyamide fibers. ACTA ACUST UNITED AC 2005. [DOI: 10.1002/pola.20739] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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