151
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Adhikari S, Joshi R, Gopinathan C. Hydrated Electrons in a Quaternary Microemulsion System: A Pulse Radiolysis Study. J Colloid Interface Sci 1997; 191:268-71. [PMID: 9241228 DOI: 10.1006/jcis.1997.4951] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Using the technique of pulse radiolysis, hydrated electrons have been produced and studied in quaternary microemulsion (sodium lauryl sulfate (NaLS)/water/cyclohexane/1-pentanol) system. Remarkably high lifetimes ( approximately 20 &mgr;s) for hydrated electrons have been obtained. In general, these are two orders of magnitude higher than those reported earlier in reverse micelles. The water droplet sizes and location of the probes have been determined from the decay kinetics of hydrated electrons. The yields and half-lives (t 1/2 ) of the hydrated electrons vary smoothly as the water droplet sizes are changed. We believe that these studies will be useful not only in interpreting electron transfer reactions occurring in small water pockets in biological systems but also in the production of metal nanoclusters by radiation chemical method.
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Affiliation(s)
- S Adhikari
- Chemistry Division, Bhabha Atomic Research Centre, Bombay, 400 085, India
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152
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Grand D, Dokutchaev A. Does the Interfacial Potential Control the Charge Separation Efficiency in Reverse Micellar Media? J Phys Chem B 1997. [DOI: 10.1021/jp963884a] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- D. Grand
- URA 75, CNRS Université de Paris Sud, 91 405 Orsay Cedex, France
| | - A. Dokutchaev
- URA 75, CNRS Université de Paris Sud, 91 405 Orsay Cedex, France
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153
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Srivastava A, Krishnamoorthy G. Cell type and spatial location dependence of cytoplasmic viscosity measured by time-resolved fluorescence microscopy. Arch Biochem Biophys 1997; 340:159-67. [PMID: 9143317 DOI: 10.1006/abbi.1997.9910] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Information on the cell type and spatial location dependence of cytoplasmic viscosity would be very useful in understanding some of the processes occurring in the cell. For this purpose, fluorescent dye kiton red (sulforhodamine B) was loaded into a variety of cells such as Swiss 3T3 fibroblasts, human mononuclear cells, Sarcoma-180 tumor cells, Chinese hamster ovary cells, plant cells from Digitalis lanata, stamen hair cells of Tradescantia, and guard mother cells of Allium cepa. Space-resolved measurements of cytoplasmic viscosity were carried out by using an experimental set-up wherein a picosecond laser system was coupled with an epifluorescence microscope. The spatial resolution of this set-up was approximately 1.0 micron, and reliable dynamic fluorescence measurements could be obtained from 10(2) to 10(3) fluorescent molecules. Fluorescence lifetime measurements showed that a large fraction (approximately 70%) of kiton red was in the free form. Fluorescence anisotropy decay of kiton red in cells was analyzed by a two population (free and bound) model. The microviscosity of cytoplasm was estimated from the anisotropy decay kinetics of the free probe. It was found that the cytoplasmic viscosity is dependent on both the cell type and spatial location within a cell. Furthermore, both the average value of viscosity and spatial variation within a cell were larger in the plant cells when compared to the animal cells. Model studies in various simpler systems have shown that the higher viscosity observed in some part of the cell could be due to either physical restriction and/or the presence of high concentrations of small solutes and macromolecules.
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Affiliation(s)
- A Srivastava
- Chemical Physics Group, Tata Institute of Fundamental Research, Mumbai, India
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154
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Wang W, Vera JH. A Thermodynamic Model for the Partition of All Ionic Species in Reverse Micellar Extraction of Amino Acids with a Cationic Surfactant. SEP SCI TECHNOL 1997. [DOI: 10.1080/01496399708000955] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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155
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156
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Hasegawa M, Yamasaki Y, Sonta N, Shindo Y, Sugimura T, Kitahara A. Clustering of Aerosol OT Reversed Micelles As Studied by Nonradiative Energy Transfer of Solubilized Probes. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp961528m] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Masatoshi Hasegawa
- Department of Chemistry, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274, Japan
| | - Yuko Yamasaki
- Department of Chemistry, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274, Japan
| | - Nanae Sonta
- Department of Chemistry, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274, Japan
| | - Yoichi Shindo
- Department of Chemistry, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274, Japan
| | - Tokuko Sugimura
- Department of Chemistry, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274, Japan
| | - Ayao Kitahara
- Department of Chemistry, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274, Japan
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157
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Buriak JM, Osborn JA. Studies on Catalytic Asymmetric Imine Hydrogenation in the Presence of Reverse Micelles: Enhanced Enantioselectivity due to Surfactant Head Group Coordination. Organometallics 1996. [DOI: 10.1021/om960082t] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jillian M. Buriak
- Laboratoire de Chimie des Métaux de Transition et Catalyse, Institut le Bel, Université Louis Pasteur, Strasbourg 67000, France
| | - John A. Osborn
- Laboratoire de Chimie des Métaux de Transition et Catalyse, Institut le Bel, Université Louis Pasteur, Strasbourg 67000, France
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158
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Karukstis KK, Frazier AA, Martula DS, Whiles JA. Characterization of the Microenvironments in AOT Reverse Micelles Using Multidimensional Spectral Analysis. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp9609949] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kerry K. Karukstis
- Department of Chemistry, Harvey Mudd College, Claremont, California 91711
| | - April A. Frazier
- Department of Chemistry, Harvey Mudd College, Claremont, California 91711
| | - D. Stefan Martula
- Department of Chemistry, Harvey Mudd College, Claremont, California 91711
| | - Jennifer A. Whiles
- Department of Chemistry, Harvey Mudd College, Claremont, California 91711
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159
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García-Río L, Leis JR, Mejuto JC. Pseudophase Approach to Reactivity in Microemulsions: Quantitative Explanation of the Kinetics of the Nitrosation of Amines by Alkyl Nitrites in AOT/Isooctane/Water Microemulsions. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp953264u] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- L. García-Río
- Departamento de Química Física, Universidad de Santiago de Compostela, 15706 Santiago de Compostela, Spain
| | - J. R. Leis
- Departamento de Química Física, Universidad de Santiago de Compostela, 15706 Santiago de Compostela, Spain
| | - J. C. Mejuto
- Departamento de Química Física, Universidad de Santiago de Compostela, 15706 Santiago de Compostela, Spain
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160
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Yoshino A, Okabayashi H, Uchida T, Ogasawara T, Yoshida T, O'Connor CJ. Thermally Induced Structural Change of D2O-Solubilized AOT Reversed Micelles and Base-Catalyzed H−D Exchange Reaction between Solubilized D2O Deuterium and AOT−CH Proton. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp9533988] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Akihiro Yoshino
- Department of Applied Chemistry, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466, Japan
| | - Hirofumi Okabayashi
- Department of Applied Chemistry, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466, Japan
| | - Toshihisa Uchida
- Department of Applied Chemistry, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466, Japan
| | - Toshiaki Ogasawara
- Department of Applied Chemistry, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466, Japan
| | - Tadayoshi Yoshida
- Department of Applied Chemistry, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466, Japan
| | - Charmian J. O'Connor
- Department of Chemistry, The University of Auckland, Private Bag 92019, Auckland 1, New Zealand
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161
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Hasegawa M, Sugimura T, Shindo Y, Kitahara A. Structure and properties of AOT reversed micelles as studied by the fluorescence probe technique. Colloids Surf A Physicochem Eng Asp 1996. [DOI: 10.1016/0927-7757(96)03463-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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162
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Paul B, Mukherjee D, Moulik S. Charge transfer and fluorescence behaviour of hexylamine and 7,7,8,8-tetracyanoquinodimethane in compartmentalized (reverse micelle and microemulsion) and non-aqueous environments. J Photochem Photobiol A Chem 1996. [DOI: 10.1016/1010-6030(95)04202-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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163
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Xie JW, Xu JG, Chen GZ. Sensitized room temperature phosphorescence of biacetyl in AOT reversed micelles-dodecylammonium α-naphthylacetate as energy donor. Anal Chim Acta 1996. [DOI: 10.1016/0003-2670(95)00477-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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164
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Suzuki K, Harada M, Shioi A. Growth mechanism of cadmium sulfide ultrafine particles in water-in-oil microemulsion. JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 1996. [DOI: 10.1252/jcej.29.264] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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165
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D'Angelo M, Fioretto D, Onori G, Palmieri L, Santucci A. High-frequency dielectric properties of aerosol sodium bis-2-ethyl-hexylsulfosuccinate (AOT)-H2O-CCl4 systems in the reversed micellar phase. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1995; 52:R4620-R4623. [PMID: 9964089 DOI: 10.1103/physreve.52.r4620] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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166
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167
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Study of the dynamics of water/aerosol OT/n-heptane system by dielectric relaxation measurements. Colloid Polym Sci 1995. [DOI: 10.1007/bf00657641] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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168
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Xie JW, Xu JG, Chen GZ. Study on strongly polarized water in AOT reversed micelles by fluorescence probes and analytical application of AOT reversed micelles. Anal Chim Acta 1995. [DOI: 10.1016/0003-2670(95)00202-b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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169
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170
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Enzyme reactions in reverse micelles. ACTA ACUST UNITED AC 1995. [DOI: 10.1016/s0167-4501(06)80154-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
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171
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Melo EP, Aires-Barros MR, Cabral JM. Triglyceride hydrolysis and stability of a recombinant cutinase from Fusarium solani in AOT-iso-octane reversed micelles. Appl Biochem Biotechnol 1995; 50:45-56. [PMID: 7535515 DOI: 10.1007/bf02788039] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A recombinant cutinase from Fusarium solani was encapsulated in AOT reversed micelles. Physicochemical parameters of the system were optimized relative to triolein hydrolysis. Kinetic studies of triglyceride hydrolysis showed a decrease in specificity with increase of the acyl chain length. Stability of cutinase in the system under study is lower than in aqueous solution and decreases with increase in the water content in the system (W0 = [H2O]/[AOT]). The products of triolein hydrolysis had little effect on the cutinase stability. Although glycerol did not alter the stability, oleic acid decreases the enzyme stability. The increase in log P of solvent (from iso-octane to n-dodecane) decreased the stability. Deactivation profiles were fitted with the Henley and Sadana model (1).
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Affiliation(s)
- E P Melo
- Laboratório de Engenharia Bioquímica, Instituto Superior Técnico, Lisbon, Portugal
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172
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173
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Komives CF, Lilley E, Russell AJ. Biodegradation of pesticides in nonionic water-in-oil microemulsions of tween 85: Relationship between micelle structure and activity. Biotechnol Bioeng 1994; 43:946-59. [DOI: 10.1002/bit.260431008] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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174
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Gębicki JL, Gębicka L, Kroh J. Electron processes in AOT reverse micelles. Part 1.—Absorption spectra and lifetimes of hydrated electrons as studied by pulse radiolysis. ACTA ACUST UNITED AC 1994. [DOI: 10.1039/ft9949003411] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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175
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Dorovska-Taran VN, Veeger C, Visser AJ. Comparison of the dynamic structure of alpha-chymotrypsin in aqueous solution and in reversed micelles by fluorescent active-site probing. EUROPEAN JOURNAL OF BIOCHEMISTRY 1993; 211:47-55. [PMID: 8425550 DOI: 10.1111/j.1432-1033.1993.tb19868.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A highly fluorescent anthraniloyl (Ant) group was covalently attached to the active site of alpha-chymotrypsin (CT), probably at Ser195. Ant-CT is stable at neutral pH for months, allowing a detailed fluorescence study of Ant-CT as a model protein to investigate its physical properties in 0.1 M Tris/HCl, pH 8.2, and in reversed micelles of n-octane, 0.1 M Tris/HCl, pH 8.2, and sodium bis(2-ethylhexyl)sulfosuccinate (AOT). Steady-state fluorescence measurements of the progressive red-shift of the center of gravity of the emission band as function of degree of hydration, wo, defined as [H2O]/[AOT], indicate that the average polarity in the vicinity of the probe is approaching that of bulk water at wo > 12. Time-resolved fluorescence measurements of Ant-CT in water and in reversed micelles showed that the active site has different properties in reversed micelles compared to those in water. Some specific changes at very low water content (0.6 < wo < 5) can be observed, which correlate with enzyme activity measurements in the same wo region (unpublished results). These effects are, for instance, significant changes in the average fluorescence lifetime and the internal flexibility of the probe. The overall rotational-correlation time of the enzyme in AOT reversed micelles seems to be independent on wo (5 < wo < 29), which suggests that the enzyme creates its own micelle.
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Affiliation(s)
- V N Dorovska-Taran
- Department of Biochemistry, Agricultural University Wageningen, The Netherlands
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176
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Ponton A, Nozaki R, Bose TK. Dielectric relaxation study of oil‐continuous microemulsion systems. J Chem Phys 1992. [DOI: 10.1063/1.463369] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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177
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Effects of Aerosol OT reversed micelles on the formation of chemiluminescent Schiff bases with phenylacetaldehyde and amino acids. Anal Chim Acta 1992. [DOI: 10.1016/0003-2670(92)85064-d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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178
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A Fourier transform infrared study of water—head group interactions in reversed micelles containing sodium bis(2-ethylhexyl) sulfosuccinate (AOT). J Colloid Interface Sci 1992. [DOI: 10.1016/0021-9797(92)90047-p] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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179
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Estimation of the aggregation number and core radius of microemulsions. MONATSHEFTE FUR CHEMIE 1992. [DOI: 10.1007/bf00817593] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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180
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Vijayalakshmi CS, Gulari E. Extraction of Trivalent Metals and Separation of Binary Mixtures of Metals Using Winsor II Microemulsion Systems. SEP SCI TECHNOL 1992. [DOI: 10.1080/01496399208018872] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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181
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182
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183
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Shin DM, Kim SW, Shim SC. POLARIZATION STUDY OF 5(E)-STYRYL-1,3-DIMETHYL URACIL IN DIISOOCTYL SULFOSUCCINATE (AEROSOL-OT) REVERSED MICELLE SOLUTIONS. Photochem Photobiol 1991. [DOI: 10.1111/j.1751-1097.1991.tb01981.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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184
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Rees GD, da Graca Nascimento M, Jenta TR, Robinson BH. Reverse enzyme synthesis in microemulsion-based organo-gels. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1073:493-501. [PMID: 1707672 DOI: 10.1016/0304-4165(91)90221-2] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Lipase from three different sources has been immobilised in microemulsion-based gels (MBGs) with retention of catalytic activity. Such lipase-containing MBGs prove to be novel solid-phase catalysts for use in apolar organic solvents such as n-heptane. Using these systems, preparative-scale synthesis of a wide variety of esters under mild conditions was possible with products easily isolated and obtained in high yield. Stereoselective esterification of octan-2-ol was observed for all three lipases with Chromobacterium viscosum (CV) lipase yielding product with an enantiomeric excess of 92%. Repeated usage of a CV lipase-containing MBG resulted in a visually unchanged gel whose activity was 75% of the initial value after 30 days. The sectioned MBGs were well suited for use in column flow reactors and were also found to be effective esterification catalysts at temperatures as low as -20 degrees C.
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Affiliation(s)
- G D Rees
- School of Chemical Sciences, University of East Anglia, Norwich, U.K
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185
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Karpe P, Ruckenstein E. The enzymatic superactivity in reverse micelles: Role of the dielectric constant. J Colloid Interface Sci 1991. [DOI: 10.1016/0021-9797(91)90350-h] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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186
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DEROUICHE A, TONDRE C. CORRELATION BETWEEN MAXIMUM WATER/ELECTROLYTE SOLUBILIZAT1ON AND CONDUCTIVITY PERCOLATION IN AOT REVERSED MICELLES. J DISPER SCI TECHNOL 1991. [DOI: 10.1080/01932699108913150] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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187
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188
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189
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Karpe P, Ruckenstein E. Effect of hydration ratio on the degree of counterion binding and pH distribution in reverse micelles with aqueous core. J Colloid Interface Sci 1990. [DOI: 10.1016/0021-9797(90)90416-l] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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190
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Abstract
Physicochemical investigations on the aggregation of phospholipids (mainly phosphatidylcholines) in organic solvents are reviewed and compared with the aggregation behaviour of phospholipids in aqueous medium. In particular we review the data showing that phosphatidylcholines (lecithins) form reverse micellar structures in certain apolar solvents. In these systems not only low molecular weight compounds but also catalytically active enzymes and entire cells can be solubilized. In addition, highly viscous phosphatidylcholine gels can be obtained in organic solvents upon solubilizing a critical amount of water. Generally, phospholipid-based reverse micelles can be regarded as thermodynamically stable models for inverted micellar lipid structures possibly occurring in biological membranes.
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Affiliation(s)
- P Walde
- ETH-Zentrum, Institut für Polymere, Zürich, Switzerland
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191
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Jolivalt C, Minier M, Renon H. Extraction of α-chymotrypsin using reversed micelles. J Colloid Interface Sci 1990. [DOI: 10.1016/0021-9797(90)90290-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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192
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Harada M, Shinbara N, Adachi M, Miyake Y. Liquid membrane operation with aid of microemulsion. Separation of metal ions. JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 1990. [DOI: 10.1252/jcej.23.50] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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193
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Interfacial micropolarity in the micellar region of the sodium (2-ethylhexyl) sulfosuccinate (AOT) inverted micelles. J Colloid Interface Sci 1990. [DOI: 10.1016/0021-9797(90)90278-v] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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194
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Escobar L, Salvador C, Contreras M, Escamilla JE. On the application of the Clark oxygen electrode to the study of enzyme kinetics in apolar solvents: the catalase reaction. Anal Biochem 1990; 184:139-44. [PMID: 1690958 DOI: 10.1016/0003-2697(90)90026-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A method for recording O2 concentrations in nonconducting organic media with the Clark oxygen electrode was developed. Spontaneous oxidation of Na2S2O4 and the enzymatic reduction of NaBO3 or H2O2 by bovine liver catalase trapped in hydrated micelles of dioctylsulfosuccinate (AOT)/toluene were used as model systems. O2 titration with the above systems showed that air-saturated 1.6 M H2O/0.2 M AOT/toluene media contain seven times more O2 (1.4 mM) than aqueous solutions (0.2 mM). The measured Km values of catalase for NaBO3 and H2O2 in organic media were Kmov = 15 and 17 mM, respectively, whereas in aqueous buffer the values were 45 and 54 mM. In the toluene media, catalase activity increased with the W0 (H2O/AOT molar ratio) of the micellar preparation, reaching maximal activity at W0 = 10-12; under this condition, the catalytic center activity (Kp) of H2O2 was 7 x 10(6) min-1, similar to that obtained in the aqueous buffer (H2O2 = 7 x 10(6) min-1). It was found that the optimal pH for catalase in toluene media (pH 8.0) was shifted 1.0 unit compared to that in the aqueous buffer (pH 7.0). On the other hand, catalase was severely inhibited by NaN3 in both media. Thus, polarography based on the Clark oxygen electrode seems to be an easy, rapid, and sensitive technique for studying enzyme reactions consuming or evolving O2 in apolar media.
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Affiliation(s)
- L Escobar
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México
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195
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Furusaki S, Kishi K. Extraction of Amino Acids by Reversed Micelles. JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 1990. [DOI: 10.1252/jcej.23.91] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Genkin M, Davydov R, Belovolova L, Yuschishina A, Kkylov O. Catalytic and redox reactions of proteins and low molecular weight reactants in reverse micelles. ACTA ACUST UNITED AC 1989. [DOI: 10.1016/0304-5102(89)80188-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Bertolini D, Cassettari M, Grigolini P, Salvetti G, Tani A. The mesoscopic physics of water and other complex systems. J Mol Liq 1989. [DOI: 10.1016/0167-7322(89)80083-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Escamilla E, Ayala G, de Gómez-Puyou MT, Gómez-Puyou A, Millán L, Darszon A. Catalytic activity of cytochrome oxidase and cytochrome c in apolar solvents containing phospholipids and low amounts of water. Arch Biochem Biophys 1989; 272:332-43. [PMID: 2546496 DOI: 10.1016/0003-9861(89)90227-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Cytochrome c and cytochrome oxidase, in bovine heart submitochondrial particles and in their purified forms, were transferred to a ternary system that contained phospholipids (10 mg/ml toluene), the apolar solvent toluene, and water at concentrations of 13-15 microliters (high water) and 3 microliters (low water) per milliliter of toluene. When the enzymes were transferred back to an all water system, they exhibited full catalytic capacity. In the low water ternary system, cytochrome c could be reduced by ascorbate introduced via inverted micelles. Also in this system, cytochrome oxidase was reduced by ascorbate and cytochrome c but its oxidation was highly impaired. Data on the kinetics of reduction by ascorbate of cytochrome c and cytochrome oxidase under these conditions are presented. Cytochrome oxidase reduced in the organic solvent by ascorbate failed to form a complex with CO, but formed a complex with cyanide introduced via inverted micelles. The oxidized and the ascorbate-reduced cytochrome oxidase-cyanide complex exhibited a trough at 415 nm and a peak at 433 nm. The extent and rate of formation of the cyanide complex were higher with the reduced form of cytochrome oxidase. To achieve protein-protein interactions (cytochrome c-cytochrome oxidase) in the ternary system, it was necessary to extract the two proteins together. There was no functional interaction when they were extracted separately and mixed. In the high water ternary system reduced cytochrome oxidase was not detected, and it oxidized ascorbate at a higher rate than in the low water system; however, this rate was several orders of magnitude lower than in aqueous media.
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Affiliation(s)
- E Escamilla
- Instituto de Fisiologia Celular, Universidad Nacional Autónoma de México, DF
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