PEROXIDASE CATALYZED GENERATION OF TRIPLET ACETONE |
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| Authors: | Etelvino J H Bechara Olga M M Faria Oliveira Nelson Duran ‡ Roberto Casadei de Baptista Giuseppe Cilento |
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| Institution: | Department of Biochemistry, Instituto de Quimica, Universidade de SBo Paulo. C.P. 20780;, SHo Paulo, Brazil |
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| Abstract: | Abstract— Triplet acetone generated in the isobutanal/horseradish peroxidase/O, system is quenched by collisional agents of the diene type. A Stern-Volmer analysis indicates that collision is considerably impeded, the barrier being largely entropic. Triplet-triplet energy transfer to biacetyl is also observed. Quenching of triplet acetone by energy transfer to 9 ,10-dibromoanthracene-2-sulfonate (DBAS) is a much faster process than energy transfer to these collisional agents, in accordance with the earlier inference that transfer to DBAS is a long-range triplet-singlet transfer process. The fraction of the triplet acetone which undergoes reduction to isopropanol is not interceptable by quenchers.
Absorption and circular dichroism studies suggest that peroxidase shuttles between Compound II and I when generating the precursor hydroperoxide. |
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