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

被引:54
作者
Kane, MA [1 ]
Baker, GA [1 ]
Pandey, S [1 ]
Bright, FV [1 ]
机构
[1] SUNY Buffalo, Dept Chem, Buffalo, NY 14260 USA
关键词
D O I
10.1021/la991604n
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
We report the first results on an enzyme-induced reaction within the water core of reverse micelles that have been formed in supercritical CO2 (scCO(2)). By using a perfluoropolyether ammonium carboxylate (PFPE) surfactant, we form reverse micelles in scCO(2) with water cores and we show that the oxidation of cholesterol by cholesterol oddase (ChOx) obeys Michaelis-Menten kinetics. The results of our experiments also show that (1) the optimum ChOx activity occurs when the molar ratio of H2O-to-PFPE (R) exceeds similar to 12, (2) the rate constant describing the conversion of the ChOx-cholesterol complex to product (k(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-m,K-app) is optimal at high R values, (4) the best-case K-m,K-app is similar to 2-fold better than the value reported alkanes, (5) there is little change in the ChOx k(cat,app) and K-m,K-app as we adjust the CO2 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.
引用
收藏
页码:4901 / 4905
页数:5
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