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Wichmann C, Naumann PT, Spangenberg O, Konrad M, Mayer F, Hoppert M. Liposomes for microcompartmentation of enzymes and their influence on catalytic activity. Biochem Biophys Res Commun 2003; 310:1104-10. [PMID: 14559229 DOI: 10.1016/j.bbrc.2003.09.128] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Modular systems for protein coupling have been applied for anchoring enzyme molecules on liposome surfaces. Two cytoplasmic model enzymes, alpha-amylase from Escherichia coli (EC. 3.2.1.1) and guanylate kinase from Saccharomyces cerevisiae (EC. 2.7.4.8), were directly coupled by a histidine-tag or indirectly via strep-tag and streptavidin or streptactin linker to a liposome membrane. Though the catalytic properties of the enzymes are generally maintained, stability and specific activity of the enzymes are modified after coupling and are especially influenced by the lipid used for the liposome assembly.
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Affiliation(s)
- C Wichmann
- Institut für Mikrobiologie und Genetik der Universität Göttingen, Grisebachstrasse 8, 37077 Göttingen, Germany
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Hancer M, Patist A, Kean R, Muralidhara H. Micellization and adsorption of phospholipids and soybean oil onto hydrophilic and hydrophobic surfaces in nonaqueous media. Colloids Surf A Physicochem Eng Asp 2002. [DOI: 10.1016/s0927-7757(01)01097-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Melo EP, Aires-Barros MR, Cabral JM. Reverse micelles and protein biotechnology. BIOTECHNOLOGY ANNUAL REVIEW 2002; 7:87-129. [PMID: 11686050 DOI: 10.1016/s1387-2656(01)07034-x] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Reverse micelles are nanometer-sized (1-10 nm) water droplets dispersed in organic media obtained by the action of surfactants. Surfactant molecules organize with the polar part to the inner side able to solubilize water and the apolar part in contact with the organic solvent. Proteins can be solubilized in the water pool of reverse micelles. Studies on the structure-function relationships of proteins in reverse micelles are very important since the microenvironment in which the protein is solubilized has physico-chemical properties distinct from a bulk aqueous solution. Some of the unique characteristics of reverse micelles make them very useful for biotechnological applications. Charge and hydrophilic/hydrophobic characteristics of the protein and the selection of surfactant can be used to achieve selective solubilization of proteins. This has been used to extend the classical liquid-liquid extraction with solvents to protein bioseparation. For biocatalysis the presence of a bulk organic solvent allow synthetic reactions to be performed via the control of water content and the solubilization of hydrophobic substrates. This is accomplished with a higher interfacial area (about 100 m2/mL) than the conventional biphasic systems, minimizing mass transfer problems.
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Affiliation(s)
- E P Melo
- Universidade do Algarve-F.E.R.N., Campus de Gambelas, 8000 Faro, Portugal.
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Willard DM, Levinger NE. Influence of Morphology on Polar Solvation Dynamics in Lecithin Reverse Micelles. J Phys Chem B 2000. [DOI: 10.1021/jp002076n] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dale M. Willard
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872
| | - Nancy E. Levinger
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872
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Sommerville ML, Cain JB, Johnson CS, Hickey AJ. Lecithin inverse microemulsions for the pulmonary delivery of polar compounds utilizing dimethylether and propane as propellants. Pharm Dev Technol 2000; 5:219-30. [PMID: 10810752 DOI: 10.1081/pdt-100100537] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Lecithin inverse microemulsions were investigated as a means of pulmonary drug delivery, utilizing dimethylethyleneglycol (DMEG) and hexane as models for dimethyl ether (DME) and propane, respectively. Addition of lecithin to the model propellant mixtures increased the solubility of water in a nonlinear, solvent-dependent manner. The concentration of water necessary to fully hydrate cobalt(II) decreased as the solvent composition was varied from DMEG to hexane. Water proton chemical shift increased in the presence of lecithin, with the largest increases in high hexane content samples. Equilibrium dialysis and component diffusion rate determination (by pulsed-field gradient [PFG]-NMR) indicated the quantity of water associated with the dispersed phase. Collectively, these methods demonstrated that a greater fraction of water was associated with the microemulsion-dispersed phase as the solvent was varied from DMEG to hexane. Iodine solubilization indicated microemulsion formation (operational critical micelle concentration [cmc], 10 moles water per mole lecithin) at approximately 10(-4)-10(-5) molal lecithin. NMR data (trimethylammonium proton chemical shift, water, and lecithin T1) were consistent with microemulsion formation. Water-soluble compounds dissolved in lecithin inverse microemulsions in a lecithin- and water-dependent manner. Experiments with DME/lecithin demonstrated microemulsion characteristics similar to those in the model propellant. DME/lecithin metered-dose inhalers (MDIs) produced a particle size and a fine particle fraction (36% by twin impinger method) suitable for pulmonary drug delivery.
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Affiliation(s)
- M L Sommerville
- School of Pharmacy, University of North Carolina, Chapel Hill 27514-7360, USA
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Willard DM, Riter RE, Levinger NE. Dynamics of Polar Solvation in Lecithin/Water/Cyclohexane Reverse Micelles. J Am Chem Soc 1998. [DOI: 10.1021/ja980086k] [Citation(s) in RCA: 202] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Dale M. Willard
- Contribution from the Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872
| | - Ruth E. Riter
- Contribution from the Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872
| | - Nancy E. Levinger
- Contribution from the Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872
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Rodriguez R, Vargas S, Fernandez-Velasco DA. Reverse Micelle Systems Composed of Water, Triton X-100, and Phospholipids in Organic Solvents. J Colloid Interface Sci 1998; 197:21-8. [PMID: 9466839 DOI: 10.1006/jcis.1997.5202] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Enzymes entrapped in systems formed with water, phospholipids, toluene, and Triton X-100 show a catalytic activity that is much lower and a thermostability that is much higher than that observed in totally aqueous systems or in other types of reverse micelles. By phase boundary titrations and dynamic light scattering, this work characterizes reverse micelle systems formed in either toluene or propylbenzene with Triton X-100 and water. Four regions with distinct structural features were encountered. Up to one molecule of water per one Triton X-100 molecule, the system was transparent; light scattering measurements of this region indicated that water hydrated Triton X-100 monomers. A turbid region was formed as water content was increased to water:Triton X-100 ratios of 7.6 in toluene and 4.2 in propylbenzene. This thermodynamically unstable region was formed by large polydisperse structures. Transparent systems containing small size (27-150 A) thermodynamically stable reverse micelles were formed when the ratio of water to Triton X-100 molecules in the reverse micelle was in the range of 7.6 to 26.8 in toluene and 4.2 to 15.1 in propylbenzene. In this region, micellar size increased with water content. Water concentrations higher than the latter values resulted in phase separation. A similar titration of the aforementioned systems in the presence of phospholipids revealed that in the first region of transparency up to 10 molecules of water hydrated a phospholipid molecule. The inclusion of phospholipids to the Triton X-100 systems caused a displacement of the boundaries of the second region of transparency toward higher water contents. Copyright 1998 Academic Press. Copyright 1998Academic Press
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Affiliation(s)
- R Rodriguez
- Departamento de Fisica, Universidad Autonoma Metropolitana-Iztapalapa, D.F. 09340, Mexico
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Fernandez-Velasco DA, Rodriguez R, Vargas S, Gomez-Puyou A. Reverse Micelle Systems Composed of Water, Triton X-100, and Phospholipids in Organic Solvents. J Colloid Interface Sci 1998; 197:29-35. [PMID: 9466840 DOI: 10.1006/jcis.1997.5203] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Catalysis, stability, and thermostability of yeast hexokinase were determined in the microenvironments of two organic solvent/Triton X-100/phospholipids systems. In the abscence of enzyme, phase diagrams showed two transparent/turbid transitions, and reverse micelles were only observed in the second region of transparency (T2), where particle size as a function of water content shows a minima (see previous paper in this issue). In the present work, enzyme activity was detected throughout the four regions of the phase diagrams of these systems. Catalysis increased with water content; nevertheless, the maximum activities that were reached in the toluene and propylbenzene systems were 30 and 1.6%, respectively, of the activity in all aqueous media. Because in the T2 region in the propylbenzene system, micelles are much smaller than in toluene (see preceding paper), it would appear that expression of catalysis depends on the size of the micelles. However, a comparison of the dimensions of hexokinase and those of reverse micelles in the T2 region, suggests that in this region, hexokinase entrapment increases the inner volume of the micelle. High enzyme thermostability was only observed in the first transparent region (T1) of the system that contained phospholipids. In this region, hexokinase induced the formation of reverse micelles from dispersed surfactant monomers. There is a striking similarity in the dimensions of hexokinase entrapped in reverse micelles as determined by dynamic light scattering measurements in the T1 region with those of hexokinase as obtained from X ray diffraction studies of the enzyme in a crystalline environment. This suggest that high thermostability, and low catalytic rates result from restrictions in mobility imposed by a low water environment. Copyright 1998 Academic Press. Copyright 1998Academic Press
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Affiliation(s)
- DA Fernandez-Velasco
- Facultad de Medicina, Universidad Nacional Autonoma de Mexico, D.F. 04510, Mexico
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Egger D, Wehtje E, Adlercreutz P. Characterization and optimization of phospholipase A2 catalyzed synthesis of phosphatidylcholine. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1343:76-84. [PMID: 9428661 DOI: 10.1016/s0167-4838(97)00115-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The phospholipase A2 (PLA2) catalyzed synthesis and hydrolysis of phosphatidylcholine (PC) was studied in a water activity controlled organic medium. The aim of the study was to find the conditions most favorable for the synthetic reaction. To do this, the impact of various parameters such as water activity, substrate concentration and temperature on enzyme activity and equilibrium yield was determined. The PC to lysophosphatidylcholine (LPC) ratio at equilibrium increases with decreasing water activity and increasing fatty acid concentration, as can be expected from the law of mass action of an esterification reaction. The enzyme activity on the other hand decreases under conditions that favor the esterification. The best yield in the synthetic reaction is 60% at a water activity of 0.11 and an oleic acid concentration of 1.8 M. That is to our knowledge the highest yield ever reported in this reaction. Both the hydrolysis and synthesis reaction follow Michaelis-Menten kinetics, the apparent Km values are the same for PC and LPC, namely 4.9 mM. Vmax is 82.5 and 10.4 nmol h(-1) mg(-1) for the hydrolysis and synthesis reaction, respectively. Studies on PLA2 at water activity controlled conditions resulted in a more complete understanding of the enzymatic reaction and allowed to find the conditions most favorable for the synthetic reaction.
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Affiliation(s)
- D Egger
- Department of Biotechnology, Center for Chemistry and Chemical Engineering, Lund University, Sweden.
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Avramiotis S, Bekiari V, Lianos P, Xenakis A. Structural and Dynamic Properties of Lecithin-Alcohol Based w/o Microemulsions: A Luminescence Quenching Study. J Colloid Interface Sci 1997; 194:326-31. [PMID: 9398413 DOI: 10.1006/jcis.1997.5135] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Water-in-oil microemulsions have been made with lecithin in the presence of some alcohols. The structure of the microemulsions has been studied by steady-state and time-resolved analysis of the luminescence quenching of Ru(bipy)32+ by Fe(CN)63-. We found that well-defined microemulsions can be made only in the presence of short-chain alcohols such as propanol-1 and butanol-1. There exists a threshold for water content in order to obtain typical reverse micelles. Thus in the case of propanol-1, water/surfactant ratio wo should be above 20. By varying water content in the range 20 < wo </= 40, the microemulsion droplets suffer dramatic structural changes and the system passes through a percolation threshold. Copyright 1997 Academic Press. Copyright 1997Academic Press
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Affiliation(s)
- S Avramiotis
- Institute of Biological Research and Biotechnology, National Hellenic Research Foundation, 48 Vas. Constantinou Avenue, Athens, 11635, Greece
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Giustini M, Palazzo G, Colafemmina G, Della Monica M, Giomini M, Ceglie A. Microstructure and Dynamics of the Water-in-Oil CTAB/n-Pentanol/n-Hexane/Water Microemulsion: A Spectroscopic and Conductivity Study. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp952263z] [Citation(s) in RCA: 129] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mauro Giustini
- CNR, Centro Studi Chimico-Fisici sull'Interazione Luce-Materia, c/o Dipartimento di Chimica, Università di Bari, I-70126 Bari, Italy
| | - Gerardo Palazzo
- Dipartimento di Chimica, Università di Bari, Via Orabona 4, I-70126 Bari, Italy
| | | | - Mario Della Monica
- Dipartimento di Chimica, Università di Bari, Via Orabona 4, I-70126 Bari, Italy
| | - Marcello Giomini
- Dipartimento di Chimica, Università “La Sapienza”, I-00185 Roma, Italy
| | - Andrea Ceglie
- Università del Molise, Facoltà di Agraria, I-86100 Campobasso, Italy
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Mayer F, Hoppert M. Functional compartmentalization in bacteria and archaea. Naturwissenschaften 1996. [DOI: 10.1007/bf01139309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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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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Giomini M, Giuliani A, Trotta E, Boicelli C. The use of NMR parameters for the evaluation of the critical micelle concentration of lecithin in reverse micellar systems. Chem Phys Lett 1989. [DOI: 10.1016/0009-2614(89)87347-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Luisi PL, Giomini M, Pileni MP, Robinson BH. Reverse micelles as hosts for proteins and small molecules. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 947:209-46. [PMID: 3278740 DOI: 10.1016/0304-4157(88)90025-1] [Citation(s) in RCA: 631] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- P L Luisi
- Institut für Polymere, ETH-Zürich, Switzerland
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Micelle formation of diacylglycerophosphocholine in organic solvents. II. Measurements of microenvironmental characteristics by fluorescence quenching. ACTA ACUST UNITED AC 1987. [DOI: 10.1016/0166-6622(87)80240-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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