Die Rolle des Thiolatliganden in Hämproteinen

血红素硫代蛋白或细胞色素P450酶具有特殊的催化能力，可进行羟基化、环氧化、卤化或过氧化物重排。基于我们之前的工作和由此产生的工作假设，带负电荷的硫与处于较高氧化态的血红素的电子相互作用导致稳定但仍具有活性的硫基中间体，其中与氧化还原活性硫相连的铁基和过铁基离子在自由基反应中起特殊作用。我们首次成功地在光谱上鉴定了一种血红素硫酸蛋白（P450NOR）的铁基配合物。这些研究将扩展到P450BM-3，并将铁基和过铁基中间体的反应性与非硫代血红素蛋白的反应性进行比较。

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.