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Reversed Micelles (reversed + micelle)
Selected AbstractsImprovement of the catalytic performance of lignin peroxidase in reversed micellesJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 1 2008Jing Lan Abstract BACKGROUND: Anionic surfactant sodium bis (2-ethylhexyl) sulfosuccinate (AOT) had an inhibiting effect on lignin peroxidase (LiP). To improve the catalytic activity of LiP in an AOT reversed micelle in isooctane, nonionic surfactant polyoxyethylene lauryl ether (Brij30) was incorporated into the interfacial membrane. H2O2 played dual roles in the LiP-catalyzed oxidation of substrates. To obtain a sustainable high activity of LiP, a coupled enzymatic reaction, i.e. the glucose oxidase (GOD)-catalyzed oxidation of glucose was used as an H2O2 source. RESULTS: Owing to modification of the charge density of the interfacial membrane, the activity of LiP in an optimized AOT/Brij30 reversed micellar medium (,B (the molar percentage of Brij30) = 0.53, ,0 ([H2O]/([AOT] + [Brij30]) = 23, pH = 4.8) was 40 times that in a single AOT reversed micelle. Due to the controlled release of H2O2, the concentration of H2O2 in the mixed reversed micellar medium was maintained at a moderately high level throughout, which made the LiP-catalyzed oxidation of substrates proceed at a higher conversion rate than counterparts in which H2O2 was supplied externally in one batch at the beginning of the reaction. Decolourization of two waterless-soluble aromatic dyes (pyrogallol red and bromopyrogallol red) using LiP coupled with GOD in the medium also demonstrated that a higher decolourization percentage was obtained if H2O2 was supplied enzymatically. CONCLUSION: The proposed measures (both physicochemical and biochemical) were very effective, giving significant improvement in the catalytic performance of LiP in a single AOT reversed micelle in isooctane, which helped to degrade or transform hydrophobic aromatic compounds with LiP in reversed micelles more efficiently. Copyright © 2007 Society of Chemical Industry [source] Localization and interactions of melatonin in dry cholesterol/lecithin mixed reversed micelles used as cell membrane modelsJOURNAL OF PINEAL RESEARCH, Issue 4 2005David Bongiorno Abstract:, The state of melatonin confined in dry cholesterol/lecithin mixed reversed micelles dispersed in CCl4 was investigated using 1H-NMR and FT-IR spectroscopies as a function of the melatonin to lecithin molar ratio (RMLT) and of the cholesterol to lecithin molar ratio (RCHL). An analysis of experimental results leads to the hypothesis that, independent of RMLT and as a consequence of anisotropic melatonin/lecithin, melatonin/cholesterol and cholesterol/lecithin interactions, melatonin is totally solubilized in reversed micelles. Melatonin is mainly located in and oriented in the nanodomain constituted by the hydrophilic groups of cholesterol and lecithin. A competition of melatonin and cholesterol for the hydrophilic binding sites of the reversed micelles was observed by changing the RCHL. Some possible biological implications of the specific interactions governing the solubilization process, the preferential location and the peculiar properties of melatonin confined in cholesterol/lecithin mixed reversed micelles are discussed. [source] Fluorescence saturation of dye molecules in water pools of reversed micellesLASER PHYSICS LETTERS, Issue 10 2005A. V. Potapov Abstract Rhodamine 6G has been used as a fluorescence probe in AOT reversed micelles systems with the different amounts of solubilized water (hydratation power ,). The saturation of fluorescence and the lifetime of dye molecules were measured. The absorption cross section values were calculated from the saturation curves. We showed the differences in values of the absorption cross section, lifetime and velocity of fluorescence saturation in micellar phase with different , and in comparison to bulk phase. Additionally, the structure of hydrated reversed micelles has been studied by the method of correlation spectroscopy. The influence of , on size and shape of micelles was detected. (© 2005 by Astro, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] Direct Refolding of Inclusion Bodies Using Reversed MicellesBIOTECHNOLOGY PROGRESS, Issue 6 2004Masafumi Sakono The protein refolding of inclusion bodies was investigated using reversed micelles formed by aerosol OT (AOT). Ribonuclease A (RNase A) was overexpressed in Escherichia coli and used as native inclusion bodies. The enzymatic activity of RNase A was completely regained from the inclusion bodies within 14 h by solubilization in reversed micelles. To further enhance the refolding rate, a molecular chaperone, GroEL, was incorporated into the refolding system. The resultant refolding system including GroEL showed better performance under optimized conditions for the refolding of RNase A inclusion bodies. The refolding rate was considerably improved by the addition of the molecular chaperone, and the refolding step was completed in 1 h. The protein refolding in the GroEL-containing refolding system was strongly dependent on the coexistence of ATP and Mg2+, suggesting that the GroEL hosted in the reversed micelles was biologically active and assisted in the renaturation of the inclusion bodies. The addition of cold acetone to the reversed micellar solution allowed over 90% recovery of the renatured RNase A. [source] | ||||||||||