Objective To assess the effects of hepatitis B virus(HBV) large envelope protein (LHB) on the apoptosis of HepG2 cells and explore the possible mechanism by proteomic approaches.Methods LHB gene was cloned into pShuttle-IRES-hrGFP-1,and the recombinant adenovirus either barboring LHB(Ad-LHB) or empty vector(Ad-GFP) were separately generated.Annexin V-FITC apoptosis detection kit,JC-1 mitochondrial membrane potential assay kit and propidium iodide(PI) staining kit were employed combined with flow cytometry to detect the apoptotic cells infected with Ad-LHB or control of Ad-GFP.The cellular proteins were collected after infection of HepG2 cells by Ad-LHBs or Ad-GFP,and a total of 600 μg proteins were submitted to two-dimensional gel electrophoresis(2-DE) and stained with R350.The gel images were captured by ImageScanner Ⅱ Imaging System,the differentially expressed proteins were identified by ImageMaster 2D Platinum analysis software and picked up by Ettan Spot Picker.After enzyme digestion,the protein samples were analyzed by MALDI-TOF-TOF MS.Results HepG2 cells infected with Ad-LHB were much more prone to apoptosis.There were thirty nine differentially expressed proteins were determined by 2-DE between HepG2 cells infected with Ad-LHB and Ad-GFP,and they were identified ultimately and categorized into thirty three kinds of proteins by MALDI-TOF-TOF MS.Among these proteins,nine were found to be closely related to cell apoptosis,in which CAPN2,eIF3K and PPP2CB were higher expressed in Ad-LHB infected HepG2 cells,and SERPINH1,LASP1,PRDX1,DHRS2,LDHA and PS-MA4 were lower expressed in Ad-LHB infected HepG2 cells.Conclusion LHB could induce apoptosis of HepG2 cells,and several apoptosis-related proteins participated in this process.