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New Enzyme Models of Chloroperoxidase: Improved stability and catalytic efficiency of iron porphyrinates containing a thiolato ligand
Author(s) -
Wagenknecht HansAchim,
Claude Cécile,
Woggon WolfDietrich
Publication year - 1998
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19980810554
Subject(s) - chemistry , ligand (biochemistry) , adduct , catalysis , redox , heme , enzyme , medicinal chemistry , stereochemistry , photochemistry , turnover number , inorganic chemistry , organic chemistry , receptor , biochemistry
The heme‐thiolate protein chloroperoxidase (CPO) catalyzes the chlorination of activated CH bonds. A reaction mechanism is proposed for this enzymatic transformation ( Scheme 1 ), and a new iron(III) porphyrinate complex 13 is synthesized containing pentafluorophenyl groups at two meso ‐positions and a thiophenolato ligand coordinating to the Fe‐atom ( Schemes 2 and 3 ). Due to the presence of the electron‐withdrawing substituents, the catalyst 13 is appreciably resistant to oxidants (HOCl) and chlorinates, e.g. , monochlorodimedone ( 5 ), with turnover numbers up to 1530. The redox potential of 13 , E 0 = ‐ 134 mV, and the Soret band (λ max 448 nm) of the CO adduct of the reduced state of 13 are close to the corresponding values of the enzyme CPO.