Study on Splitting of Sucrose Glycoside Bonds by beta-Fructosidase of Aspergillus niger VKM F-801

O. S. Korneeva^*, N. A. Zherebtsov, I. V. Cheremushkina, and E. Yu. Ukhina

Voronezh State Technological Academy, pr. Revolyutsii 19, Voronezh, 394017 Russia; fax: (0732) 55-4267

^* To whom correspondence should be addressed.

Received April 3, 1998; Revision received May 7, 1998

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Functional groups of beta-fructosidase of Aspergillus niger VKM F-801 were identified. Based on the pH dependence of the enzyme, the calculated heat of ionization, the photoinactivation of the enzyme in the presence of methylene blue photosensitizer, and also the enzyme inactivation by diethyl pyrocarbonate, the catalytic center of the beta-fructosidase was found to include carboxyl and imidazole groups of amino acid residues. The glycoside bond in the sucrose molecule is apparently cleaved by the catalytically active carboxylate--imidazole pair.

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KEY WORDS: beta-fructosidase, hydrolysis, photooxidation, catalytic mechanism

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