Immobilization of α-chymotrypsin into the poly(N,N-diallyl-N,N-didodecyl ammonium bromiae)/surfactant nanocapsules |
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Authors: | Yury E Shapiro Elena G Pykhteeva |
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Institution: | (1) Life Sciences, Bar-llan University, 52900 Ramat-Gan, Israel;(2) Bogatsky Physico-Chemical Institute, National Academy of Sciences, 270080 Odessa, Ukraine |
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Abstract: | The biocatalytic systems from nanocapsules containing α-chymotrypsin in the inner aqueous cavities have been prepared. They
can act in both the organic solvent and the aqueous medium. For such encapsulation, the reversed hydrated micelles from N,N-diallyl-N,N-didodecyl
ammonium bromide (DDAB) in cyclohexane (w0 = 22), including α-chymotrypsin, have been polymerized by UV initiation. After precipitation by acetone, these nanocapsules
were moved into the aqueous medium with the aid of ionic, AOT, or nonionic, Brij-97, surfactants. In this case, the unilamellar
liposomes were formed. They have the inner monolayer from the poly-DDAB network, and the outer one predominantly from surfactant
molecules. According to the light-scattering data, the average outer diameter of nanocapsules equals to 20 nm. The vesicular
“coated” α-chymotrypsin was used for study of enzymatic activity. It has been shown using the integral form of the Michaelis-Menten
equation, that by encapsulation of α-chymotrypsin the value of the Michaelis constant, Km, increases by a factor of 1.8 by the ATEE hydrolysis. However, the value of the maximal velocity, Vmax, decreases by a factor of 1.7. Encapsulated α-chymotrypsin has a high thermostability keeping its own activity up to 80°C.
The polymer network blocks the conformational transitions of enzyme molecule by heating of a system. |
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Keywords: | α -Chymotrypsin immobilized biocatalyst enzyme in the net nanocapsules monomer surfactants AOT Brij-97 enzymatic activity thermostability |
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