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Title: Performance of cholesterol oxidase sequestered within reverse micelles formed in supercritical carbon dioxide

Abstract

The authors report the first results on an enzyme-induced reaction within the water core of reverse micelles that have been formed in supercritical CO{sub 2} (scCO{sub 2}). By using a perfluoropolyether ammonium carboxylate (PFPE) surfactant, the authors form reverse micelles in scCO{sub 2} with water cores and the authors show that the oxidation of cholesterol by cholesterol oxidase (ChOx) obeys Michaelis-Menten kinetics. The results of their experiments also show that (1) the optimum ChOx activity occurs when the molar ratio of H{sub 2}O-to-PFPE (R) exceeds {approximately}12, (2) the rate constant describing the conversion of the ChOx-cholesterol complex to product ({kappa}{sub cat,app}) is similar to values reported using reverse micelle systems formed in liquid alkanes, (3) the equilibrium constant that describes the ChOx-cholesterol complex dissociation (K{sub m,app}) is optimal at high R values, (4) the best-case K{sub m,app} is {approximately}2-fold better than the value reported using reverse micelles formed in liquid alkanes, (5) there is little change in the ChOx {kappa}{sub cat,app} and K{sub m,app} as the authors adjust the CO{sub 2} pressure between 100 and 260 bar, and (6) the ChOx was active within the PFPE water pool for at least 5 h; however, after 8 or more hours withinmore » the PFPE water pool, ChOx became temporarily inactive.« less

Authors:
; ; ;
Publication Date:
Research Org.:
State Univ. of New York, Buffalo, NY (US)
OSTI Identifier:
20080284
Resource Type:
Journal Article
Journal Name:
Langmuir
Additional Journal Information:
Journal Volume: 16; Journal Issue: 11; Other Information: PBD: 30 May 2000; Journal ID: ISSN 0743-7463
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CARBON DIOXIDE; SUPERCRITICAL STATE; CHOLESTEROL; OXIDOREDUCTASES; MICELLAR SYSTEMS

Citation Formats

Kane, M.A., Baker, G.A., Pandey, S., and Bright, F.V. Performance of cholesterol oxidase sequestered within reverse micelles formed in supercritical carbon dioxide. United States: N. p., 2000. Web. doi:10.1021/la991604n.
Kane, M.A., Baker, G.A., Pandey, S., & Bright, F.V. Performance of cholesterol oxidase sequestered within reverse micelles formed in supercritical carbon dioxide. United States. doi:10.1021/la991604n.
Kane, M.A., Baker, G.A., Pandey, S., and Bright, F.V. Tue . "Performance of cholesterol oxidase sequestered within reverse micelles formed in supercritical carbon dioxide". United States. doi:10.1021/la991604n.
@article{osti_20080284,
title = {Performance of cholesterol oxidase sequestered within reverse micelles formed in supercritical carbon dioxide},
author = {Kane, M.A. and Baker, G.A. and Pandey, S. and Bright, F.V.},
abstractNote = {The authors report the first results on an enzyme-induced reaction within the water core of reverse micelles that have been formed in supercritical CO{sub 2} (scCO{sub 2}). By using a perfluoropolyether ammonium carboxylate (PFPE) surfactant, the authors form reverse micelles in scCO{sub 2} with water cores and the authors show that the oxidation of cholesterol by cholesterol oxidase (ChOx) obeys Michaelis-Menten kinetics. The results of their experiments also show that (1) the optimum ChOx activity occurs when the molar ratio of H{sub 2}O-to-PFPE (R) exceeds {approximately}12, (2) the rate constant describing the conversion of the ChOx-cholesterol complex to product ({kappa}{sub cat,app}) is similar to values reported using reverse micelle systems formed in liquid alkanes, (3) the equilibrium constant that describes the ChOx-cholesterol complex dissociation (K{sub m,app}) is optimal at high R values, (4) the best-case K{sub m,app} is {approximately}2-fold better than the value reported using reverse micelles formed in liquid alkanes, (5) there is little change in the ChOx {kappa}{sub cat,app} and K{sub m,app} as the authors adjust the CO{sub 2} pressure between 100 and 260 bar, and (6) the ChOx was active within the PFPE water pool for at least 5 h; however, after 8 or more hours within the PFPE water pool, ChOx became temporarily inactive.},
doi = {10.1021/la991604n},
journal = {Langmuir},
issn = {0743-7463},
number = 11,
volume = 16,
place = {United States},
year = {2000},
month = {5}
}