Synthetic active site analogues of heme-thiolate proteins. Characterization and identification of intermediates of the catalytic cycles of cytochrome P450cam and chloroperoxidase |
| |
Authors: | Woggon W D Wagenknecht H A Claude C |
| |
Institution: | Institute of Organic Chemistry, University of Basel, Switzerland. wolf-d.woggon@unibas.ch |
| |
Abstract: | In view of recent results from different sources, the reaction mechanisms of two heme-thiolate proteins, cytochrome P450cam and chloroperoxidase (CPO), are discussed. In this context a mechanism of CPO is proposed which includes H2O2 cleavage, subsequent formation of compound I and the identification of two elusive intermediates. The HOCl adduct of the iron(III)porpyhrin is the catalytically competent Cl+ donor chlorinating activated C-H bonds of substrates bound to the enzyme. Pulse-EPR characterization of an enzyme model of the resting state of P450cam suggests a role of the electric field of the protein for stabilizing the low-spin state of the cofactor of the enzyme. It is further suggested that the same effect of the protein may trigger the reactivity of compound I such that both concerted and two-step reactions are feasible within the concept of a Two-State-Reactivity. This review emphasizes the value of synthetic enzyme models complementing investigations of the native proteins. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|