Die Rolle des Thiolatliganden in Hämproteinen

• Applicant: Professor Dr. Volker Ullrich
• Subject Area: Metabolism, Biochemistry and Genetics of Microorganisms
• Term: from 1999 to 2004
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5176966

Heme-thiolate proteins or cytochrome P450 enzymes are of mechanistical interest because of their special catalytic abilities in performing hydroxylations, epoxidations, halogenations or rearrangements of peroxides. Based on our previous work and the resulting working hypothesis the electronic interaction of the negatively charged sulfur with heme in its higher oxidation states leads to stabilized but still reactive thiyl intermediates, from which the ferryl and perferryl ion linked to the redox-active sulfur play a special role in the catalysis of radical reactions. We succeeded for the first time to spectroscopically identify a ferryl complex of a heme-thiolate protein (P450NOR). Such investigations will be expanded to P450BM-3 and the reactivities of the ferryl and perferryl intermediates will be compared to those of the non-thiolate heme proteins.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1071: Radikale in der enzymatischen Katalyse