MOLECULAR PROBES OF THE MECHANISM OF CYTOCHROME P-450

肺、肝、肾和上皮组织的细胞色素P-450是 已知在致癌物活化、药物和异生物质 解毒以及类固醇和前列腺素代谢。 这个的目标 程序是阐明有机和无机化学的 由细胞色素P-450介导的过程统称为氧- 活化和底物氧化。 我们双管齐下的方法 (i)利用细胞色素P-450的底物， 看不见的中间体和（ii）开发模型系统作为化学 这些过程的范例。 这些研究的一个重要方面是 直接比较酶和模型反应， 实验室 为下一个赠款期提议的具体活动是： 1. 含氧铁卟啉的结构和反应活性。 含氧铁卟啉配合物的结构和相互转化 继续提供有关化学事件性质的见解 称为氧活化。 我们计划制备氢过氧铁（III） 卟啉配合物和相关的含氧物种，并观察其 转化为反应性络合物，例如氧代铁（IV）卟啉阳离子 根的 我们还将探讨制定类似的战略， 与血红素的生物学相关的硫醇盐连接的复合物 铁. 2. 复溶膜中的P-450模型。 我们计划使用合成和半合成磷脂组件， 模拟和理解P-450作用的电子转移事件， 膜环境 具体而言，我们将：（1）设计模型膜- 卟啉系统，可以促进难以捉摸的铁（III）- 硫醇盐配位环境;（2）探索鉴别方法 膜结合卟啉空间取向及相关氧化还原 组件，以了解向量过程的一般;（3） 探索我们最近的发现，膜结合的氧化还原酶， 细胞色素P-450还原酶、细胞色素b5和丙酮酸氧化酶可 与合成膜氧化还原伙伴有效沟通。 3. DNA作为底物;双链和单链的选择性反应 链dna 我们计划设计水溶性金属卟啉和相关的非卟啉 金属配合物，并探索选择性的DNA和RNA链切割与 这些物种。 这一努力可能会导致试剂的选择性， 氧化裂解的寡核苷酸，并可能提供新的基础 基于氧代金属的抗肿瘤和抗病毒化合物家族 细胞色素P-450化学 我们还计划研究DNA切割 阳离子卟啉衍生物与两种金属配位的反应 附件和探索物种与铁蛋白mRNA的相互作用。

The cytochrome P-450 of lung, liver, kidney, and epithelial tissue are known to play a central role in carcinogen activation, drug and xenobiotic detoxification and steroid and prostaglandin metabolism. The goals of this program are to elucidate the organic and inorganic chemistry of the processes mediated by cytochrome P-450 referred to collectively as oxygen- activation and substrate oxygenation. Our two-pronged approach has been (i) to employ substrates for cytochrome P-450 designed to reveal the nature of unseen intermediates and (ii) to develop model systems as chemical paradigms for these processes. An important aspect of these studies has been the direct comparison of enzymic and model reactions in the same laboratory. Specific activities proposed for the next grant period are: 1. Structure and Reactivity of Oxygenated Iron Porphyrins. The structure and interconversions of oxygenated iron porphyrin complexes continue to afford insight regarding the nature of the chemical events referred to as oxygen activation. We plan to prepare hydroperoxoiron(III) porphyrin complexes and related oxygenated species and observe their conversion to reactive complexes such as oxoiron(IV) porphyrin cation radicals. We will also explore strategies for the preparation of similar complexes with the biologically relevant thiolate ligation of the heme iron. 2. P-450 MOdels in Reconstituted Membranes. We plan to use synthetic and semi-synthetic phospholipid assemblies to model and understand the electron transfer events on P-450 action in membrane environments. Specifically, we will: (1) devise model membrane- porphyrin systems which can facilitate the study of the elusive iron(III)- thiolate coordination environment; (2) explore methods of differentiating the spatial orientation of membrane bound porphyrins and related redox components toward an understanding of vectorial processes in general; (3) explore our very recent finding that membrane bound redox enzymes such as cytochrome P-450 reductase, cytochrome b5, and pyruvate oxidase can communicate effectively with synthetic membrane redox partners. 3. DNA as a Substrate; Selective Reactions of Double-Stranded and Single- Stranded DNA. We plan to design water-soluble metalloporphyrins and related non-porphyrin metal complexes and to explore selective DNA and RNA strand cutting with these species. The effort may result in reagents for the selective, oxidative cleavage of oligonucleotides and may provide the basis for new families of antitumor and antiviral compounds based on the oxometal chemistry of cytochrome P-450. We plan also to study the DNA cleavage reactions of derivatives of cationic porphyrins with two metal coordinating appendages and to explore interactions of the species with ferritin mRNA.