Prokaryotic Expression And Activity Research Of Culex Quinquefasciatus Protease Inhibitor

Under the long-term environmental pressure, haematophagous arthropods have evolved perfect mechanisms to have a successful blood meal. The saliva from blood-feeding arthropods contains much bioactivator which could inhibit hemagglutin -ation, inflammatory reaction, immunoreaction of host in blood meal. Most blood-feeders is a great potential treasure of biological resources which could regulate hemagglutination, inflammatory reaction, immunoreaction.According to the specific active site of residues, protease inhibitor is divided into four categories:aspartic proteases inhibitor, metalloproteinases inhibitor, serine proteases inhibitor and cysteine proteases inhibitor. Accordingly, the protease inhibitors are divided into four kinds. By action mechanism, serine protease inhibitors can be divided into three types:canonical, non-canonical, serpin(serine protease inhibitors).Culex quinquefasciatus is a common kind of Culex in china, it spreads some infections such as filariasis and epidemic encephalitis B etc.In This research object we constructe Culex quinquefasciatus A3199 gene.By E. coli pET expression system, A3199 is successfully expressed with trypsin inhibitor activity. The purified A3199 is 7861.5 daltons, consistent with the prediction. The Ki for A3199 is about 15.3264 uM,which is determined by Dixon plot.