海南产桶形芋螺蛋白质二硫键异构酶的鉴定

蛋白质二硫键异构酶(PDI)是内质网新生肽链折叠中一个重要的折叠酶.在热 带药用海洋生物芋螺的毒液中富含PDI酶，该酶对于毒液中芋螺毒素神经肽的体内 氧化折叠至关重要.本研究主要采用凝胶过滤层析和制备型Rotofor液相等电聚焦 电泳等多种方法，从海南产桶形芋螺（Conus betulinus Linnaeus）毒管中分离 纯化天然的PDI酶蛋白，经电泳和MALDI-TOF MS质谱鉴定分析确证获得了高纯度 的桶形芋螺PDI酶，建立了天然芋螺PDI酶分离纯化的技术方法. 以芋螺毒素线性 肽K412为底物进行了PDI酶活性鉴定.结果表明,该分离纯化的PDI酶能够促进K412 的氧化折叠.由于芋螺毒素的氧化折叠非常复杂，且氧化折叠后具有正确二硫键连 接方式的芋螺毒素才具有各种药理活性，因此，本研究结果为后续PDI酶在种类繁 多的芋螺毒素氧化折叠中的应用及其作用机制研究提供了重要的物质基础.

ICharacterization of Protein Disulfide Isomerase of Conus Betulinus Linnaeus Native to Hainan

The protein disulfide isomerase (PDI) is an important foldase to fold the nascent polypeptide chain in the endoplasmic reticulum (ER). PDI is rich in the venom of tropic officinal marine cone snails and is important in facilitating the folding and maturation of secretory conopeptides in vivo. The natural PDI was prepared from the venom of Conus betulinus native to Hainan by gel-filtration chromatography and Rotofor preparative liquid-phase isoeletric focusing electrophoresis, and the purity was analyzed by SDS-PAGE and MALDI-TOF MS. Following our optimized protocol for the purification of natural Conus PDI, the catalytical activity of the obtained PDI was tested using linear conopeptide K412 as the substrate for oxidative folding. Among the complexed forms of the conopeptides following oxidative folding, only the ones with the proper disulfide bond formation exert pharmacological activities. Our preparation would be useful for the further studies on the PDI application in the oxidative folding of a great variety of conopeptides.