Development of a novel enzymatic synthesis method for trehalose derivatives and its application

本论文旨在开发海藻糖衍生物的新型酶促合成方法及其在杀虫剂和抗真菌药物中的应用。海藻糖是一种二糖，常见于真菌、藻类和几种无脊椎动物门，但不存在于开花植物和脊椎动物中。它存在于所有昆虫中，在许多昆虫中以高浓度存在，并构成主要的血淋巴糖。海藻糖是家蚕卵巢发育过程中血淋巴海藻糖合成糖原过程的限速酶，可水解海藻糖。我们从盐单胞菌Halomonassp. A-15中分离纯化了葡萄糖-3-脱氢酶，并发现其具有产生海藻糖衍生物的活性。其中一种衍生物3，3 '-二酮基海藻糖对海藻糖具有抑制活性，因此我们研究了其作为杀虫剂或抗真菌化学品的活性。它没有表现出抗真菌活性，但它可以是一种杀虫剂。并对高效生产工艺进行了研究，发现酶法生产比微生物法生产效率更高。以铁氰化钾为电子受体，采用高纯度的葡萄糖-3-脱氢酶，产率可达80%。因此，我们建立了一种高效生产3，3 '-二酮基海藻糖的方法，它可以作为一种新型的高效杀虫剂，对动物无害。

We aimed at the development of novel enzymatic synthesis method of the trehalose derivatives and those applications to insecticides or anti-fungal chemicals. Trehalose is a disaccharide and commonly found in fungi, algae and in several invertebrate phyla but not in flowering plants and vertebrates. It presents in all insects and in many insects it is present in high concetration s and constitutes the major hemolymph sugar. Trehalose secifically hydrolyzed trehalose and is the rate-limiting enzyme in the process of glycogen synthesis from hemolymph trehalose in developing ovaries of the silkworm. Therefore the specific inhibitor for trehalases is a candidate of novel insecticides.We purified glucose-3-dehydrogenase from Halomonas sp. A -15 and found its activity to produce trehalose derivatives. One of those derivatives, 3,3'-diketotrehalose showed an inhibitory activity to trehalose, and therefore we investigated its activity as insecticide or anti-fungal chemicals. It did not show anti-fungal activity but it can be an insecticide. We also investigated its efficient production process, and found the enzymatic production is more efficient than microbial production. By using potassium ferricyanide as electron acceptor and the highly purified glucose-3-dehydrogenase, 80% productivity was attained. Hence we established efficient method to produce 3,3'-diketotrehalose, it can contribute as a novel effective insecticide which is not harmful to animals.