Cytochrome P450 Enzymes: Identification, Diversity, and Potential Functions in Marine Invertebrates

小行星9631128 细胞色素P450酶可能是自然界中最多样化的蛋白质家族。 它们存在于迄今为止所研究的所有生物体中，并具有广泛的代谢外来化学物质（外源性物质）和内源性分子（如类固醇和脂肪酸）的能力。 P450多样化的驱动力之一被认为是饮食中有毒化学物质的出现，即所谓的植物-动物战争假说。 在哺乳动物中，一个个体中可能存在一百种或更多种P450形式，每种形式都有自己的代谢能力。同样，昆虫似乎有大量的P450形式，一些涉及杀虫剂和膳食植物化感物质抗性。海洋无脊椎动物也有明显的P450酶活性，可通过暴露于污染物诱导，但几乎没有什么是已知的解毒酶在海洋无脊椎动物的作用，以膳食化学品。 关于这组酶的新信息可能有助于解释个别物种的饮食和代谢方面，以及确定影响对其他外源性暴露的耐受性的因素。 研究者建议利用分子克隆的方法来分离和鉴定新的细胞色素P450基因从几个海洋无脊椎动物物种代表三个不同的门（目的1）。 这些数据将首次估计海洋无脊椎动物中这一大型蛋白质超家族的多样性。将在实地收集的物种和受控实验室饲养实验中研究属于该家族的选定新蛋白质的基因表达诱导（目的2）。 将产生几种新形式的抗体，用于设计灵敏的免疫学测定，以测量P450对毒素暴露的诱导作用（目的3）。由于目前还没有已知的海洋无脊椎动物P450序列，这些研究将提供急需的信息，这些重要的酶的多样性。 这些结果将有助于比较海洋生物和陆地生物解毒酶的进化和功能。 最终的目标是开发方法，测试物种接触天然和人工毒物后的特异性反应。

9631128 Snyder Cytochrome P450 enzymes are perhaps the most diverse family of proteins in nature. They are found in all organisms thus far examined and have extensive abilities to metabolize foreign chemicals (xenobiotics) and endogenous molecules such as steroids and fatty acids. One of the driving forces for P450 diversification is thought to be the appearance of toxic chemicals in the diet, the so-called plant-animal warfare" hypothesis. In mammals, one hundred or more P450 forms may exist in a single individual, each with its own metabolic capabilities. Likewise, insects appear to have a large number of P450 forms, some involved in insecticide and dietary plant allelochemical resistance. Marine invertebrates also have demonstrable P450 enzymatic activities that are inducible by exposure to pollutants, though virtually nothing is known about the role of detoxification enzymes in marine invertebrate to dietary chemicals. New information on this group of enzymes may help explain aspects of individual species diet and metabolism as well as identify factors that affect tolerance to other xenobiotic exposures. The investigator proposes to utilize molecular cloning approaches to isolate and identify new cytochrome P450 genes from several marine invertebrate species representing three different Phyla (Aim 1). Those data will provide the first estimate of the diversity of this large protein superfamily among marine invertebrates. The induction of gene expression for selected new proteins belonging to this family will be studied in both field collected species and in controlled laboratory feeding experiments (Aim 2). Antibodies will be produced to several new forms for the design of sensitive immunological assays to measure P450 induction in response to toxin exposures (Aim 3). Since there are currently no marine invertebrate P450 sequences known, these studies will provide much needed information about the diversity of these important enzymes. The results will allow comparisons concer ning the evolution and functions of detoxification enzymes between marine and terrestrial organisms. An eventual goal is the development of methods that will test species-specific responses following exposure to natural and artificial toxicants.