New Enzyme Models of Chloroperoxidase: Improved stability and catalytic efficiency of iron porphyrinates containing a thiolato ligand

✍ Scribed by Hans-Achim Wagenknecht; Cécile Claude; Wolf-Dietrich Woggon

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: German
• Weight: 773 KB
• Volume: 81
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19980810554

✦ Synopsis

Abstract

The heme‐thiolate protein chloroperoxidase (CPO) catalyzes the chlorination of activated CH 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.