Ethylene Glycol and the Thermostability of Trypsin in a Reverse Micelle System

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E. A. Stupishina, R. N. Khamidullin, N. N. Vylegzhanina, D. A. Faizullin, and Yu. F. Zuev^*

Kazan Institute of Biochemistry and Biophysics, Russian Academy of Sciences, 420111 Kazan, P. Box 30, Russia; fax: (8432) 292-7347; E-mail: zuev@mail.knc.ru

^* To whom correspondence should be addressed.

Received June 10, 2005; Revision received September 20, 2005

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The influence of ethylene glycol (EG) on the kinetics of hydrolysis of N-alpha-benzoyl-L-arginine ethyl ether catalyzed by trypsin encapsulated in sodium bis-(2-ethylhexyl)sulfosuccinate (AOT)-based reverse micelles was studied at different temperatures. Ethylene glycol was shown to shift the range of the trypsin activity in the reverse micelles towards higher temperatures. Infrared spectroscopy showed a stabilizing effect of EG on the secondary structure of the protein in the system of reverse micelles. Electron spin resonance spectroscopy showed that the solubilized protein affected the interactions of EG with the polar head groups of AOT and altered the rigidity of the micellar matrix. The results indicate that EG increases the thermostability of the solubilized enzyme in microemulsion media by two mechanisms.

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KEY WORDS: reverse micelles, ethylene glycol, trypsin, thermostability

DOI: 10.1134/S0006297906050105

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