Reactivation of Heterodimer and Individual Subunits of Penicillin Acylase from E. coli after Inactivation in Urea

T. A. Shamolina and V. K. Svedas^*

Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119899 Russia; fax: (095) 939-3181; E-mail: vytas@enzyme.genebee.msu.su

^* To whom correspondence should be addressed.

Received August 3, 1999; Revision received September 3, 1999

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Individual subunits of penicillin acylase from E. coli were isolated by gel-filtration under denaturing conditions (8 M urea). Recovery of the catalytic activity of the penicillin acylase heterodimer was studied after removal of urea. In the case of the heterodimer, 40-60% of the initial activity was recovered, whereas the activity of individual subunits was not recovered. Combination of native enzyme subunits with subunits isolated from the enzyme pre-inactivated with the irreversible inhibitor phenylmethylsulfonyl fluoride resulted in heterodimers which were active only in the case of involvement of the beta-subunit of the active enzyme.

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KEY WORDS: penicillin acylase, subunits, reactivation

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