ELECTROCATALYTIC STUDIES OF TOXIC POLLUTANT ACTIVATION

我们的环境受到有机污染物的污染产生了 严重的当代公共卫生问题。重大机制 导致人类疾病的因素包括有机物质的毒性激活 污染物进入人体后。该工艺以氧化为特征。 在肝脏中细胞色素P450酶催化的污染物中， 随之而来的是遗传物质(即DNA)被激活 污染物。以这种方式激活的化学物质包括苯乙烯， 苯并[a]芘，还有许多其他的。有机卤化物污染物，如 氯二恶英和多氯联苯不那么容易被激活， 但它们提高了体内细胞色素P450的水平，促进了 出现代谢功能障碍的可能性。例如，过量的细胞色素P450 可催化膜脂或其他有害物质的氧化 功能性生物分子。这些氧化产物也可能损害DNA。 了解毒素的分子细节和酶的特异性 活化和DNA损伤可以带来新的方法来处理由 并改善我国公民未来的健康状况。 该项目的长期目标是开发新的薄膜。 活化DNA损伤体外研究中的电极涂层 污染物，以及激活的新化学物质的简单毒性筛查 通过酶。具体目标包括开发基于以下内容的系统 电极驱动的酶催化污染物活化，使用酶 和DNA通过浇铸和层层生长法制备的薄膜。 系统将被设计成模拟污染物的自然有毒激活 和DNA损伤。使用的酶将来自一种模型血红素蛋白， 肌红蛋白，细菌细胞色素P450，人细胞色素P450。 可能包括细胞色素P450酶的天然氧化还原伙伴 如果需要的话，在电影里。目标设备将使用电子注入 从电极驱动一系列涉及酶催化的事件 污染物的活化，以及被活化的污染物对DNA的损伤。 电化学和层析分析将被用于监测DNA 胶片上的损坏。毒性筛查化验的验证工作将由 已知有毒污染物的DNA损伤率与 致突变性和致癌性数据库。除了新设备之外 对于有毒化学物质的筛选，这一项目将导致相对 建立人类详细底物特异性的简便方法 细胞色素P450，其相对分布可能很重要 个人对污染物引起的疾病的易感性。

Contamination of our environment with organic pollutants generates serious contemporary public health problems. A major mechanism contributing to human disease involves toxic activation of organic pollutants after they enter the body. This process features oxidation of the pollutants catalyzed by cytochrome P450 enzymes in the liver, followed by damage of genetic material (i. e. DNA) by activated pollutants. Chemicals activated in this way include styrene, benzo[a]pyrene, and many others. Organohalide pollutants such as chlorodioxins and polychlorinated biphenyls are not as easily activated, but they elevate cytochrome P450 levels in the body, promoting the chance of metabolic dysfunction. For example, excess cytochrome P450 can catalyze undesirable oxidation of membrane lipids or other functional biomolecules. These oxidation products may also damage DNA. Knowledge of molecular details and enzyme specificities of toxic activation and DNA damage can lead to new ways to treat pollutant-caused diseases and improve the future health of our citizens. The broad long-term goals of this project are to develop new, thin-film electrode coatings for in-vitro studies of DNA damage by activated pollutants, and as simple toxicity screens for new chemicals activated by enzymes. Specific aims include developing systems based on electrode-driven enzyme-catalyzed pollutant activation, using enzymes and DNA in thin films prepared by casting and layer-by-layer growth. Systems will be designed to mimic natural toxic activation of pollutants and DNA damage. Enzymes used will proceed from a model heme protein, myoglobin, to bacterial cytochrome P450, to human cytochromes P450. Natural redox partners of the cytochrome P450 enzymes may be included in the films if needed. Target devices will employ electron injection from electrodes to drive a series of events involving enzyme-catalyzed pollutant activation, and damage of DNA by the activated pollutants. Electrochemical and chromatographic analyses will be used to monitor DNA damage in the films. Validation of toxic screen assays will be done by correlating DNA damage rates for known toxic pollutants with mutagenicity and carcinogenicity data bases. In addition to new devices for screening toxic chemicals, this project will result in relatively simple probes for establishing detailed substrate specificities of human cytochrome P450s, the relative distribution of which may be important in individual susceptibility to pollutant-caused disease.