메뉴 건너뛰기




Volumn 4, Issue 1, 2000, Pages 74-80

Biocatalysis in low-water media: Understanding effects of reaction conditions

Author keywords

[No Author keywords available]

Indexed keywords

BACTERIAL ENZYME;

EID: 0033965918     PISSN: 13675931     EISSN: None     Source Type: Journal    
DOI: 10.1016/S1367-5931(99)00055-1     Document Type: Review
Times cited : (105)

References (55)
  • 3
    • 0032479388 scopus 로고    scopus 로고
    • Lipases: Interfacial enzymes with attractive applications
    • Schmid R.D., Verger R. Lipases: interfacial enzymes with attractive applications. Angew Chem Int Ed. 37:1998;1609-1633.
    • (1998) Angew Chem Int Ed , vol.37 , pp. 1609-1633
    • Schmid, R.D.1    Verger, R.2
  • 4
    • 0032167489 scopus 로고    scopus 로고
    • Microbial lipases form versatile tools for biotechnology
    • Jaeger K.E., Reetz M.T. Microbial lipases form versatile tools for biotechnology. Trends Biotechnol. 16:1998;396-403.
    • (1998) Trends Biotechnol , vol.16 , pp. 396-403
    • Jaeger, K.E.1    Reetz, M.T.2
  • 7
    • 0032993482 scopus 로고    scopus 로고
    • Effects of metal salts on the structure and activity of alpha-chymotrypsin in ethanol water
    • Sasaki T., Kise H. Effects of metal salts on the structure and activity of alpha-chymotrypsin in ethanol water. Bull Chem Soc Jpn. 72:1999;1321-1325.
    • (1999) Bull Chem Soc Jpn , vol.72 , pp. 1321-1325
    • Sasaki, T.1    Kise, H.2
  • 8
    • 0033591415 scopus 로고    scopus 로고
    • Drastic enhancement of the enantioselectivity of lipase-catalysed esterification in organic solvents by the addition of metal ions
    • Aqueous salt solutions were added to isopropyl-ether-based reaction mixtures for esterification of phenoxypropionic acids. Whereas water alone increased rates with both enantiomers, LiCl inhibited reaction of the wrong enantiomer. Enantioselectivity at the optimum final LiCl concentration of around 12 mM was five-times better than with water alone.
    • Okamoto T., Ueji S. Drastic enhancement of the enantioselectivity of lipase-catalysed esterification in organic solvents by the addition of metal ions. Chem Commun. 1999;939-940. Aqueous salt solutions were added to isopropyl-ether-based reaction mixtures for esterification of phenoxypropionic acids. Whereas water alone increased rates with both enantiomers, LiCl inhibited reaction of the wrong enantiomer. Enantioselectivity at the optimum final LiCl concentration of around 12 mM was five-times better than with water alone.
    • (1999) Chem Commun , pp. 939-940
    • Okamoto, T.1    Ueji, S.2
  • 9
    • 0033586348 scopus 로고    scopus 로고
    • Protein refolding in predominantly organic media markedly enhanced by common salts
    • Aqueous lysozyme solutions denatured by 8 M urea were diluted into aqueous-organic mixtures (usually 60% solutions of various diols). Some refolding to catalytically active lysozyme occurs, and the yield is greater in the presence of certain salts. For example, 1 M LiCl in 80% ethylene glycol raises the yield from 3% to 22%. The mechanism is thought to involve salting-in of forms that would otherwise aggregate irreversibly.
    • Rariy R.V., Klibanov A.M. Protein refolding in predominantly organic media markedly enhanced by common salts. Biotechnol Bioeng. 62:1999;704-710. Aqueous lysozyme solutions denatured by 8 M urea were diluted into aqueous-organic mixtures (usually 60% solutions of various diols). Some refolding to catalytically active lysozyme occurs, and the yield is greater in the presence of certain salts. For example, 1 M LiCl in 80% ethylene glycol raises the yield from 3% to 22%. The mechanism is thought to involve salting-in of forms that would otherwise aggregate irreversibly.
    • (1999) Biotechnol Bioeng , vol.62 , pp. 704-710
    • Rariy, R.V.1    Klibanov, A.M.2
  • 10
    • 0033586738 scopus 로고    scopus 로고
    • Optimizing the salt induced activation of enzymes in organic solvents: Effects of lyophilization time and water content
    • Subtilisin and a lipase were lyophilized to give powders of around 99% salts. As lyophilization time increased from 50 hours to 90 hours, the water content of the resulting powders progressively decreased. Catalytic activity also changed by up to 10-fold, increasing at first, then decreasing.
    • Ru M.T., Dordick J.S., Reimer J.A., Clark D.S. Optimizing the salt induced activation of enzymes in organic solvents: effects of lyophilization time and water content. Biotechnol Bioeng. 63:1999;233-241. Subtilisin and a lipase were lyophilized to give powders of around 99% salts. As lyophilization time increased from 50 hours to 90 hours, the water content of the resulting powders progressively decreased. Catalytic activity also changed by up to 10-fold, increasing at first, then decreasing.
    • (1999) Biotechnol Bioeng , vol.63 , pp. 233-241
    • Ru, M.T.1    Dordick, J.S.2    Reimer, J.A.3    Clark, D.S.4
  • 11
    • 0033553149 scopus 로고    scopus 로고
    • Markedly enhancing enzymatic enantioselectivity in organic solvents by forming substrate salts
    • Addition of bulky organic acids significantly improves lipase enantioselectivity with the amine PheOMe as substrate. Bulky amines have similar effects with acid substrates in reactions with subtilisin and a lipase. The effects are attributed to formation of ion-paired salts in the organic medium. Structure-based calculations indicate the counter-ion interferes more with the binding of the less-favoured enantiomer.
    • Ke T., Klibanov A.M. Markedly enhancing enzymatic enantioselectivity in organic solvents by forming substrate salts. J Am Chem Soc. 121:1999;3334-3340. Addition of bulky organic acids significantly improves lipase enantioselectivity with the amine PheOMe as substrate. Bulky amines have similar effects with acid substrates in reactions with subtilisin and a lipase. The effects are attributed to formation of ion-paired salts in the organic medium. Structure-based calculations indicate the counter-ion interferes more with the binding of the less-favoured enantiomer.
    • (1999) J Am Chem Soc , vol.121 , pp. 3334-3340
    • Ke, T.1    Klibanov, A.M.2
  • 12
    • 0033553105 scopus 로고    scopus 로고
    • Rationalization of the enantio-selectivity of subtilisin in DMF
    • Colombo G., Toba S., Merz K.M. Rationalization of the enantio-selectivity of subtilisin in DMF. J Am Chem Soc. 121:1999;3486-3493.
    • (1999) J Am Chem Soc , vol.121 , pp. 3486-3493
    • Colombo, G.1    Toba, S.2    Merz, K.M.3
  • 14
    • 0033573935 scopus 로고    scopus 로고
    • Volatile buffers can override the 'pH memory' of subtilisin catalysis in organic media
    • 'pH memory' disappears if a volatile buffer such as ammonium formate is used. Drying from buffers containing just one of these ions will cause large changes in protonation state. The role of counter-ions in controlling acid-base status is stressed.
    • Zacharis E., Halling P.J., Rees D.G. Volatile buffers can override the 'pH memory' of subtilisin catalysis in organic media. Proc Natl Acad Sci USA. 96:1999;1201-1205. 'pH memory' disappears if a volatile buffer such as ammonium formate is used. Drying from buffers containing just one of these ions will cause large changes in protonation state. The role of counter-ions in controlling acid-base status is stressed.
    • (1999) Proc Natl Acad Sci USA , vol.96 , pp. 1201-1205
    • Zacharis, E.1    Halling, P.J.2    Rees, D.G.3
  • 15
    • 0033545522 scopus 로고    scopus 로고
    • The effect of counterion, water concentration, and stirring on the stability of subtilisin BPN' in organic solvents
    • Sears P., Witte K., Wong C.H. The effect of counterion, water concentration, and stirring on the stability of subtilisin BPN' in organic solvents. J Mol Catal B. 6:1999;297-304.
    • (1999) J Mol Catal B , vol.6 , pp. 297-304
    • Sears, P.1    Witte, K.2    Wong, C.H.3
  • 16
    • 0032497415 scopus 로고    scopus 로고
    • Kinetic study of chemoselective acylation of amino-alditol by immobilized lipase in organic solvent: Effect of substrate ionization
    • When oleic acid is in excess over the co-substrate N-methylglucamine, ester synthesis becomes progressively more favoured relative to amide formation. This is attributed to protonation of the substrate amino group, making it unavailable for reaction. With an excess of base in the medium, either glucamine or a non-reactive tertiary amine, amide synthesis is favoured.
    • Maugard T., Remaud-Simeon M., Monsan P. Kinetic study of chemoselective acylation of amino-alditol by immobilized lipase in organic solvent: effect of substrate ionization. Biochim Biophys Acta. 1387:1998;177-183. When oleic acid is in excess over the co-substrate N-methylglucamine, ester synthesis becomes progressively more favoured relative to amide formation. This is attributed to protonation of the substrate amino group, making it unavailable for reaction. With an excess of base in the medium, either glucamine or a non-reactive tertiary amine, amide synthesis is favoured.
    • (1998) Biochim Biophys Acta , vol.1387 , pp. 177-183
    • Maugard, T.1    Remaud-Simeon, M.2    Monsan, P.3
  • 17
    • 0002662732 scopus 로고    scopus 로고
    • Enhancement of Candida antarctica lipase B enantioselectivity and activity in organic solvents
    • Parker M.C., Brown S.A., Robertson L., Turner N.J. Enhancement of Candida antarctica lipase B enantioselectivity and activity in organic solvents. Chem Commun. 1998;2247-2248.
    • (1998) Chem Commun , pp. 2247-2248
    • Parker, M.C.1    Brown, S.A.2    Robertson, L.3    Turner, N.J.4
  • 18
    • 0002975120 scopus 로고    scopus 로고
    • Effect of salt hydrate pair on lipase-catalyzed regioselective monoacylation of sucrose
    • Kim J.E., Han J.J., Yoon J.H., Rhee J.S. Effect of salt hydrate pair on lipase-catalyzed regioselective monoacylation of sucrose. Biotechnol Bioeng. 57:1998;121-125.
    • (1998) Biotechnol Bioeng , vol.57 , pp. 121-125
    • Kim, J.E.1    Han, J.J.2    Yoon, J.H.3    Rhee, J.S.4
  • 19
    • 0032917548 scopus 로고    scopus 로고
    • Enhancement of immobilized protease catalyzed dipeptide synthesis by the presence of insoluble protonated nucleophile
    • 2 hydrochloride was used as amino-component for a chymotrypsin reaction, rates were maximal for less-than-stoichiometric additions of triethylamine. The un-neutralised hydrochloride promotes separation of a water-rich liquid phase around the catalyst particles.
    • 2 hydrochloride was used as amino-component for a chymotrypsin reaction, rates were maximal for less-than-stoichiometric additions of triethylamine. The un-neutralised hydrochloride promotes separation of a water-rich liquid phase around the catalyst particles.
    • (1999) Enzyme Microb Technol , vol.24 , pp. 480-488
    • Barros, R.J.1    Wehtje, E.2    Adlercreutz, P.3
  • 20
    • 0029959897 scopus 로고    scopus 로고
    • Prediction of the solvent dependence of enzymatic prochiral selectivity by means of structure-based thermodynamic calculations
    • Ke T., Wescott C.R., Klibanov A.M. Prediction of the solvent dependence of enzymatic prochiral selectivity by means of structure-based thermodynamic calculations. J Am Chem Soc. 118:1996;3366-3374.
    • (1996) J Am Chem Soc , vol.118 , pp. 3366-3374
    • Ke, T.1    Wescott, C.R.2    Klibanov, A.M.3
  • 21
    • 0029818293 scopus 로고    scopus 로고
    • Rational control of enzymatic enantioselectivity through solvation thermodynamics
    • Wescott C.R., Noritomi H., Klibanov A.M. Rational control of enzymatic enantioselectivity through solvation thermodynamics. J Am Chem Soc. 118:1996;10365-10370.
    • (1996) J Am Chem Soc , vol.118 , pp. 10365-10370
    • Wescott, C.R.1    Noritomi, H.2    Klibanov, A.M.3
  • 22
    • 0032513720 scopus 로고    scopus 로고
    • Insights into the solvent dependence of chymotryptic prochiral selectivity
    • The previously reported [20] solvent effect on selectivity in acetylation of 2-(3,5-dimethoxybenzyl)-1,3-propanediol is shown to be largely attributable to effects on kinetics of the pro-R reaction. This is rationalised by modelling of the transition state structures.
    • Ke T., Klibanov A.M. Insights into the solvent dependence of chymotryptic prochiral selectivity. J Am Chem Soc. 120:1998;4259-4263. The previously reported [20] solvent effect on selectivity in acetylation of 2-(3,5-dimethoxybenzyl)-1,3-propanediol is shown to be largely attributable to effects on kinetics of the pro-R reaction. This is rationalised by modelling of the transition state structures.
    • (1998) J Am Chem Soc , vol.120 , pp. 4259-4263
    • Ke, T.1    Klibanov, A.M.2
  • 23
    • 0031770229 scopus 로고    scopus 로고
    • On the role of transition-state substrate desolvation in enzymatic enantioselectivity in aqueous-organic mixtures
    • Literature data on the effects of co-solvent addition on enantioselectivity were analysed using the authors' own method consisting of the desolvation of different parts of the isomeric transition states. In this case calculated energetics of desolvation did not explain the observed effects.
    • Luque S., Ke T., Klibanov A.M. On the role of transition-state substrate desolvation in enzymatic enantioselectivity in aqueous-organic mixtures. Biocatal Biotrans. 16:1998;233-248. Literature data on the effects of co-solvent addition on enantioselectivity were analysed using the authors' own method consisting of the desolvation of different parts of the isomeric transition states. In this case calculated energetics of desolvation did not explain the observed effects.
    • (1998) Biocatal Biotrans , vol.16 , pp. 233-248
    • Luque, S.1    Ke, T.2    Klibanov, A.M.3
  • 24
    • 0032499234 scopus 로고    scopus 로고
    • Application of structure-based thermodynamic calculations to the rationalization of the enantioselectivity of subtilisin in organic solvents
    • Enantioselectivity in the subtilisin-catalysed transesterification of 1-phenylethanol and trans-sobrerol varied up to sixfold between different solvents. The method of Wescott et al. [21] was applied to rationalise the results in this resolution, but gave only a weak correlation.
    • Colombo G., Ottolina G., Carrea G., Bernardi A., Scolastico C. Application of structure-based thermodynamic calculations to the rationalization of the enantioselectivity of subtilisin in organic solvents. Tetrahedron-Asymmetry. 9:1998;1205-1214. Enantioselectivity in the subtilisin-catalysed transesterification of 1-phenylethanol and trans-sobrerol varied up to sixfold between different solvents. The method of Wescott et al. [21] was applied to rationalise the results in this resolution, but gave only a weak correlation.
    • (1998) Tetrahedron-Asymmetry , vol.9 , pp. 1205-1214
    • Colombo, G.1    Ottolina, G.2    Carrea, G.3    Bernardi, A.4    Scolastico, C.5
  • 25
    • 0032552502 scopus 로고    scopus 로고
    • Lipase-catalyzed transesterification in organic media: Solvent effects on equilibrium and individual rate constants
    • Garcia-Alles L.F., Gotor V. Lipase-catalyzed transesterification in organic media: solvent effects on equilibrium and individual rate constants. Biotechnol Bioeng. 59:1998;684-694.
    • (1998) Biotechnol Bioeng , vol.59 , pp. 684-694
    • Garcia-Alles, L.F.1    Gotor, V.2
  • 26
    • 0032946805 scopus 로고    scopus 로고
    • Kinetics of lipase-catalysed esterification in organic media: Correct model and solvent effects on parameters
    • Janssen A.E.M., Sjursnes B.J., Vakurov A.V., Halling P.J. Kinetics of lipase-catalysed esterification in organic media: correct model and solvent effects on parameters. Enzyme Microb Technol. 24:1999;463-470.
    • (1999) Enzyme Microb Technol , vol.24 , pp. 463-470
    • Janssen, A.E.M.1    Sjursnes, B.J.2    Vakurov, A.V.3    Halling, P.J.4
  • 27
    • 0032032060 scopus 로고    scopus 로고
    • Lipase-catalyzed enantioselective esterification of ibuprofen in organic solvents under controlled water activity
    • Ducret A., Trani M., Lortie R. Lipase-catalyzed enantioselective esterification of ibuprofen in organic solvents under controlled water activity. Enzyme Microb Technol. 22:1998;212-216.
    • (1998) Enzyme Microb Technol , vol.22 , pp. 212-216
    • Ducret, A.1    Trani, M.2    Lortie, R.3
  • 28
    • 0043213963 scopus 로고    scopus 로고
    • Thermodynamic and kinetic aspects on water vs. organic solvent as reaction media in the enzyme-catalysed reduction of ketones
    • Rates and enantioselectivities were measured between -1°C and 50°C in hexane. The rate increased 16-fold between water activity 0.53 and 0.97 - a significant increase in activation enthalpy was more than compensated by a fall in entropy, -TΔS.
    • Jönsson A., Wehtje E., Adlercreutz P., Mattiasson B. Thermodynamic and kinetic aspects on water vs. organic solvent as reaction media in the enzyme-catalysed reduction of ketones. Biochim Biophys Acta. 1430:1999;313-322. Rates and enantioselectivities were measured between -1°C and 50°C in hexane. The rate increased 16-fold between water activity 0.53 and 0.97 - a significant increase in activation enthalpy was more than compensated by a fall in entropy, -TΔS.
    • (1999) Biochim Biophys Acta , vol.1430 , pp. 313-322
    • Jönsson, A.1    Wehtje, E.2    Adlercreutz, P.3    Mattiasson, B.4
  • 29
    • 0032894468 scopus 로고    scopus 로고
    • The temperature dependence of enzymatic kinetic resolutions reveals the relative contribution of enthalpy and entropy to enzymatic enantioselectivity
    • Enantioselectivity was measured for lipase-catalysed hydrolysis in water and esterification in hexane, with a variety of enzymes and substrates. Differences in activation entropy make a major contribution to discrimination in most cases. Literature data on various enzymic resolutions suggests enthalpy-entropy compensation, but this partly reflects the range of enantioselectivities that can be measured experimentally.
    • Overbeeke P.L.A., Ottosson J., Hult K., Jongejan J.A., Duine J.A. The temperature dependence of enzymatic kinetic resolutions reveals the relative contribution of enthalpy and entropy to enzymatic enantioselectivity. Biocatal Biotrans. 17:1999;61-79. Enantioselectivity was measured for lipase-catalysed hydrolysis in water and esterification in hexane, with a variety of enzymes and substrates. Differences in activation entropy make a major contribution to discrimination in most cases. Literature data on various enzymic resolutions suggests enthalpy-entropy compensation, but this partly reflects the range of enantioselectivities that can be measured experimentally.
    • (1999) Biocatal Biotrans , vol.17 , pp. 61-79
    • Overbeeke, P.L.A.1    Ottosson, J.2    Hult, K.3    Jongejan, J.A.4    Duine, J.A.5
  • 31
    • 0032478326 scopus 로고    scopus 로고
    • Effect of pressure on the catalytic activity of subtilisin Carlsberg suspended in compressed gases
    • Effects at fixed water activity were modest in compressed propane and t-amyl alcohol, but increasing pressures up to 300 bar reduced rates substantially in near-critical ethane and carbon dioxide, corresponding to large positive activation volumes.
    • Fontes N., Nogueiro E., Elvas A.M., de Sampaio T.C., Barreiros S. Effect of pressure on the catalytic activity of subtilisin Carlsberg suspended in compressed gases. Biochim Biophys Acta. 1383:1998;165-174. Effects at fixed water activity were modest in compressed propane and t-amyl alcohol, but increasing pressures up to 300 bar reduced rates substantially in near-critical ethane and carbon dioxide, corresponding to large positive activation volumes.
    • (1998) Biochim Biophys Acta , vol.1383 , pp. 165-174
    • Fontes, N.1    Nogueiro, E.2    Elvas, A.M.3    De Sampaio, T.C.4    Barreiros, S.5
  • 32
    • 0032573075 scopus 로고    scopus 로고
    • Comparison of X-ray crystal structures of an acyl-enzyme intermediate of subtilisin Carlsberg formed in anhydrous acetonitrile and in water
    • The structure of the trans-cinnamoyl intermediate formed in acetonitrile-soaked crystals is essentially the same as that formed in water. An acetonitrile molecule found in the substrate binding site of the free enzyme is displaced in the acyl-enzyme, while a second acetonitrile continues to occupy the site of the nucleophilic water in the aqueous structure. Crystals soaked in acetonitrile for long periods, or those that are air dried, have low active site contents (by phenylmethanesulfonyl fluoride [PMSF] titration) and become impermeable to a tracer dye. The authors emphasize the importance of the supramolecular structure of the crystals.
    • Schmitke J.L., Stern L.J., Klibanov A.M. Comparison of X-ray crystal structures of an acyl-enzyme intermediate of subtilisin Carlsberg formed in anhydrous acetonitrile and in water. Proc Natl Acad Sci USA. 95:1998;12918-12923. The structure of the trans-cinnamoyl intermediate formed in acetonitrile-soaked crystals is essentially the same as that formed in water. An acetonitrile molecule found in the substrate binding site of the free enzyme is displaced in the acyl-enzyme, while a second acetonitrile continues to occupy the site of the nucleophilic water in the aqueous structure. Crystals soaked in acetonitrile for long periods, or those that are air dried, have low active site contents (by phenylmethanesulfonyl fluoride [PMSF] titration) and become impermeable to a tracer dye. The authors emphasize the importance of the supramolecular structure of the crystals.
    • (1998) Proc Natl Acad Sci USA , vol.95 , pp. 12918-12923
    • Schmitke, J.L.1    Stern, L.J.2    Klibanov, A.M.3
  • 33
    • 0031958027 scopus 로고    scopus 로고
    • Physical characterization of porous materials and correlation with the activity of immobilized enzyme in organic medium
    • Barros R.J., Wehtje E., Garcia F.A.P., Adlercreutz P. Physical characterization of porous materials and correlation with the activity of immobilized enzyme in organic medium. Biocatal Biotrans. 16:1998;67-85.
    • (1998) Biocatal Biotrans , vol.16 , pp. 67-85
    • Barros, R.J.1    Wehtje, E.2    Garcia, F.A.P.3    Adlercreutz, P.4
  • 34
    • 0032486748 scopus 로고    scopus 로고
    • Mass transfer studies on immobilized alpha-chymotrypsin biocatalysts prepared by deposition for use in organic medium
    • Evidence is presented that preparations made by co-drying can show internal mass transfer limitation at high loading: saturating reaction rates at high loading; and increased specific activity on dilution with enzyme inactivated using tosyl-phenylalanine chloromethylketone.
    • Barros R.J., Wehtje E., Adlercreutz P. Mass transfer studies on immobilized alpha-chymotrypsin biocatalysts prepared by deposition for use in organic medium. Biotechnol Bioeng. 59:1998;364-373. Evidence is presented that preparations made by co-drying can show internal mass transfer limitation at high loading: saturating reaction rates at high loading; and increased specific activity on dilution with enzyme inactivated using tosyl-phenylalanine chloromethylketone.
    • (1998) Biotechnol Bioeng , vol.59 , pp. 364-373
    • Barros, R.J.1    Wehtje, E.2    Adlercreutz, P.3
  • 35
    • 0032002508 scopus 로고    scopus 로고
    • Surface active substrates essential in lipase mediated esterifications in foams
    • Aqueous media containing 100 mM oleic acid and n-alcohols a lipase are foamed by aeration, leading to up to 75% esterification.
    • Rao N.M., Haribabu M. Surface active substrates essential in lipase mediated esterifications in foams. Langmuir. 14:1998;738-740. Aqueous media containing 100 mM oleic acid and n-alcohols a lipase are foamed by aeration, leading to up to 75% esterification.
    • (1998) Langmuir , vol.14 , pp. 738-740
    • Rao, N.M.1    Haribabu, M.2
  • 36
    • 0032074323 scopus 로고    scopus 로고
    • Enzymatic glyceride synthesis in a foam reactor
    • Lauric acid in a 50% glycerol-water medium could be efficiently esterified with lipase catalysis, by aerating and forming a large foam volume.
    • Yeh Y.C., Gulari E. Enzymatic glyceride synthesis in a foam reactor. J Amer Oil Chem Soc. 75:1998;643-650. Lauric acid in a 50% glycerol-water medium could be efficiently esterified with lipase catalysis, by aerating and forming a large foam volume.
    • (1998) J Amer Oil Chem Soc , vol.75 , pp. 643-650
    • Yeh, Y.C.1    Gulari, E.2
  • 37
    • 0032590343 scopus 로고    scopus 로고
    • Characterisation of acylglycerol synthesis in aqueous foams by lipases
    • Shanmugam V.M., Sasikumar P.G., Rao N.M. Characterisation of acylglycerol synthesis in aqueous foams by lipases. J Chem Technol Biotechnol. 74:1999;515-518.
    • (1999) J Chem Technol Biotechnol , vol.74 , pp. 515-518
    • Shanmugam, V.M.1    Sasikumar, P.G.2    Rao, N.M.3
  • 38
    • 0032487739 scopus 로고    scopus 로고
    • A novel approach to biotransformations in aqueous-organic two-phase systems: Enzymatic synthesis of alkyl beta-[D]-glucosides using microencapsulated beta-glucosidase
    • The enzyme and glucose substrate were in an aqueous phase trapped inside a polymeric capsule membrane. The capsules were then suspended in neat hexanol or octanol substrates. Stability is better than for a support-adsorbed enzyme.
    • Yi Q., Sarney D.B., Khan J.A., Vulfson E.N. A novel approach to biotransformations in aqueous-organic two-phase systems: enzymatic synthesis of alkyl beta-[D]-glucosides using microencapsulated beta-glucosidase. Biotechnol Bioeng. 60:1998;385-390. The enzyme and glucose substrate were in an aqueous phase trapped inside a polymeric capsule membrane. The capsules were then suspended in neat hexanol or octanol substrates. Stability is better than for a support-adsorbed enzyme.
    • (1998) Biotechnol Bioeng , vol.60 , pp. 385-390
    • Yi, Q.1    Sarney, D.B.2    Khan, J.A.3    Vulfson, E.N.4
  • 39
    • 0000800173 scopus 로고    scopus 로고
    • Reinforced protein crystals
    • Lysozyme crystals grown in silica gels incorporate large amounts of silica, and have improved mechanical and chemical stability, but still have ordered protein, as shown here by X-ray diffraction.
    • Garcia-Ruiz J.M., Gavira J.A., Otalora F., Guasch A., Coll M. Reinforced protein crystals. Materials Res Bull. 33:1998;1593-1598. Lysozyme crystals grown in silica gels incorporate large amounts of silica, and have improved mechanical and chemical stability, but still have ordered protein, as shown here by X-ray diffraction.
    • (1998) Materials Res Bull , vol.33 , pp. 1593-1598
    • Garcia-Ruiz, J.M.1    Gavira, J.A.2    Otalora, F.3    Guasch, A.4    Coll, M.5
  • 40
    • 0033515814 scopus 로고    scopus 로고
    • Penicillin G amidase in low-water media: Immobilisation and control of water activity by means of celite rods
    • De Martin L., Ebert C., Garau G., Gardossi L., Linda P. Penicillin G amidase in low-water media: immobilisation and control of water activity by means of celite rods. J Mol Catal B. 6:1999;437-445.
    • (1999) J Mol Catal B , vol.6 , pp. 437-445
    • De Martin, L.1    Ebert, C.2    Garau, G.3    Gardossi, L.4    Linda, P.5
  • 41
    • 0032938527 scopus 로고    scopus 로고
    • Enzyme modification by polymers with solubilities that change in response to photoirradiation in organic media
    • Subtilisin was covalently attached to a methacrylate co-polymer containing spiropyran groups. The modified enzyme was soluble and active in toluene, but was precipitated by ultraviolet irradiation, which changed the spiropyran to merocyanine groups. Visible irradiation reversed the process.
    • Ito Y., Sugimura N., Kwon O.H., Imanishi Y. Enzyme modification by polymers with solubilities that change in response to photoirradiation in organic media. Nat Biotechnol. 17:1999;73-75. Subtilisin was covalently attached to a methacrylate co-polymer containing spiropyran groups. The modified enzyme was soluble and active in toluene, but was precipitated by ultraviolet irradiation, which changed the spiropyran to merocyanine groups. Visible irradiation reversed the process.
    • (1999) Nat Biotechnol , vol.17 , pp. 73-75
    • Ito, Y.1    Sugimura, N.2    Kwon, O.H.3    Imanishi, Y.4
  • 43
    • 0033525431 scopus 로고    scopus 로고
    • Optimization of Pseudomonas cepacia lipase preparations for catalysis in organic solvents
    • The lipase was prepared in different ways and rates of transesterification and competing hydrolysis determined in carbon tetrachloride, benzene and dioxane at known water activity. Specific activity (per unit protein) was at least 10-fold better for a silica-entrapped (sol-gel process) enzyme than for lyophilised powders or cross-linked crystals.
    • Secundo F., Spadaro S., Carrea G., Overbeeke P.L.A. Optimization of Pseudomonas cepacia lipase preparations for catalysis in organic solvents. Biotechnol Bioeng. 62:1999;554-561. The lipase was prepared in different ways and rates of transesterification and competing hydrolysis determined in carbon tetrachloride, benzene and dioxane at known water activity. Specific activity (per unit protein) was at least 10-fold better for a silica-entrapped (sol-gel process) enzyme than for lyophilised powders or cross-linked crystals.
    • (1999) Biotechnol Bioeng , vol.62 , pp. 554-561
    • Secundo, F.1    Spadaro, S.2    Carrea, G.3    Overbeeke, P.L.A.4
  • 44
    • 0032865394 scopus 로고    scopus 로고
    • Properties of free and immobilized lipase from Burkholderia cepacia in organic media
    • Pencreac'h G., Baratti J.C. Properties of free and immobilized lipase from Burkholderia cepacia in organic media. Appl Microbiol Biotechnol. 52:1999;276-280.
    • (1999) Appl Microbiol Biotechnol , vol.52 , pp. 276-280
    • Pencreac'h, G.1    Baratti, J.C.2
  • 47
    • 0027909364 scopus 로고
    • Solid-state nuclear-magnetic-resonance investigation of solvent dependence of tyrosyl ring motion in an enzyme
    • Burke P.A., Griffin R.G., Klibanov A.M. Solid-state nuclear-magnetic-resonance investigation of solvent dependence of tyrosyl ring motion in an enzyme. Biotechnol Bioeng. 42:1993;87-94.
    • (1993) Biotechnol Bioeng , vol.42 , pp. 87-94
    • Burke, P.A.1    Griffin, R.G.2    Klibanov, A.M.3
  • 48
    • 0032575262 scopus 로고    scopus 로고
    • Subtilisin mobility in hydrophobic organic media measured by proton NMR relaxation: Hydration is more important than solvent dielectric
    • Partridge J., Dennison P.R., Halling P.J., Moore B.D. Subtilisin mobility in hydrophobic organic media measured by proton NMR relaxation: hydration is more important than solvent dielectric. Biochim Biophys Acta. 1386:1998;79-89.
    • (1998) Biochim Biophys Acta , vol.1386 , pp. 79-89
    • Partridge, J.1    Dennison, P.R.2    Halling, P.J.3    Moore, B.D.4
  • 49
    • 0033573999 scopus 로고    scopus 로고
    • Structure, thermostability, and conformational flexibility of hen egg-white lysozyme dissolved in glycerol
    • Knubovets T., Osterhout J.J., Connolly P.J., Klibanov A.M. Structure, thermostability, and conformational flexibility of hen egg-white lysozyme dissolved in glycerol. Proc Natl Acad Sci USA. 96:1999;1262-1267.
    • (1999) Proc Natl Acad Sci USA , vol.96 , pp. 1262-1267
    • Knubovets, T.1    Osterhout, J.J.2    Connolly, P.J.3    Klibanov, A.M.4
  • 50
    • 0032517272 scopus 로고    scopus 로고
    • New insights into horseradish peroxidase function in benzene from resonance Raman spectroscopy
    • Raman signals indicate that the haem iron (III) adopts a 6-coordinate high-spin structure, unlike in water. Effects were attributed to dehydration of the active site, leading to changed hydrogen bonding, salt bridge promotion, and benzene binding as a substrate.
    • Mabrouk P.A., Spiro T.G. New insights into horseradish peroxidase function in benzene from resonance Raman spectroscopy. J Amer Chem Soc. 120:1998;10303-10309. Raman signals indicate that the haem iron (III) adopts a 6-coordinate high-spin structure, unlike in water. Effects were attributed to dehydration of the active site, leading to changed hydrogen bonding, salt bridge promotion, and benzene binding as a substrate.
    • (1998) J Amer Chem Soc , vol.120 , pp. 10303-10309
    • Mabrouk, P.A.1    Spiro, T.G.2
  • 51
    • 0033545525 scopus 로고    scopus 로고
    • Lipase-catalyzed solid-phase synthesis of sugar esters. Influence of immobilization on productivity and stability of the enzyme
    • Cao L.Q., Bornscheuer U.T., Schmid R.D. Lipase-catalyzed solid-phase synthesis of sugar esters. Influence of immobilization on productivity and stability of the enzyme. J Mol Catal B. 6:1999;279-285.
    • (1999) J Mol Catal B , vol.6 , pp. 279-285
    • Cao, L.Q.1    Bornscheuer, U.T.2    Schmid, R.D.3
  • 52
    • 0033007150 scopus 로고    scopus 로고
    • Potential of enzymatic kinetic resolution using solid substrates suspension: Improved yield, productivity, substrate concentration, and recovery
    • The performance of solid substrate suspensions can be improved compared with a reaction system in which substrates are totally dissolved, because the concentration of the favoured enantiomer need not fall as the reaction proceeds. In particular, a given enantiomeric excesses of unreacted substrate can be obtained with a higher yield.
    • Wolff A., van Asperen V., Straathof A.J.J., Heijnen J.J. Potential of enzymatic kinetic resolution using solid substrates suspension: improved yield, productivity, substrate concentration, and recovery. Biotechnol Prog. 15:1999;216-227. The performance of solid substrate suspensions can be improved compared with a reaction system in which substrates are totally dissolved, because the concentration of the favoured enantiomer need not fall as the reaction proceeds. In particular, a given enantiomeric excesses of unreacted substrate can be obtained with a higher yield.
    • (1999) Biotechnol Prog , vol.15 , pp. 216-227
    • Wolff, A.1    Van Asperen, V.2    Straathof, A.J.J.3    Heijnen, J.J.4
  • 54
    • 0033526431 scopus 로고    scopus 로고
    • Kinetics of enzymatic solid-to-solid peptide synthesis: Inter-substrate compound, substrate ratio and mixing effects
    • Erbeldinger M., Ni X-W., Halling P.J. Kinetics of enzymatic solid-to-solid peptide synthesis: inter-substrate compound, substrate ratio and mixing effects. Biotechnol Bioeng. 63:1999;316-321.
    • (1999) Biotechnol Bioeng , vol.63 , pp. 316-321
    • Erbeldinger, M.1    Ni, X.-W.2    Halling, P.J.3
  • 55
    • 84921354404 scopus 로고    scopus 로고
    • Molecular Thermodynamics of Fluid-phase Equilibria
    • Englewood Cliffs, NJ: Prentice-Hall
    • Prausnitz J.M., Lichtenthaler R.N., de Azevedo E.G. Molecular Thermodynamics of Fluid-phase Equilibria. edn 3:1998;Prentice-Hall, Englewood Cliffs, NJ.
    • (1998) Edn 3
    • Prausnitz, J.M.1    Lichtenthaler, R.N.2    De Azevedo, E.G.3


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.