Abstract: 【Objective】Toxicity Proteins among Extracellular and Intracellular produced by the strain CB6 of Xenorhabdus nematophila var. pekingensis were purified and compared in order to obtain the basic data of toxicity proteins for further study.【Method】Toxicity protein fractions from extracellular and intracellular products were purified using the technology of ammonium sulfate precipitation, DEAE-Sepharose FF chromatography, Butyl Sepharose FF chromatography, and Sephacryl S-200 HR chromatography. The protein components were analyzed with the technique of native-polyacrylamide gel electrophoresis (Native-PAGE) and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). 【Result】Two toxicity protein fractions E1 and E2 respectively from extracellular and intracellular products were purified to electrophoretic homogeneity. The growth inhibitory percentages against Helicoverpa armigera Hübner larvae was 62.63％and 97.90% with the concentrations of 2.58μg/m L E1 and 4.21μg/mL E2 respectively. A series of similar liquid chromatograms of E1 and E2 was gained through same purification procedures and parameters. Moreover, they had a similar migration location whether by native-PAGE or by SDS-PAGE. With SDS-PAGE. E1 and E2 have approximate molecular masses higher up 212kD. They still maintained inhibitory toxicity after heated up to 60℃. Staining experiments showed that the toxicity protein was neither lipoprotein nor glycoprotein.【Conclusion】This demonstrated the possibility that the target protein from extracellular section was the same as that from intracellular one.

Key words: Xenorhabdus nematophila var. pekingensis, Extracellular protein, Intracellular protein, Purification, Comparison