In order to deliver αB-crystallin (αB-C) into cardiomyocytes,the full-length cDNA fragment encoding the human αB-crystallin was cloned into the bacterial expression vector pGEX-MTS containing membrane-translocating sequence(MTS) which could mediate intracellular delivery of peptides and expressed as a fusion protein coupled to glutathione S-transferase(GST).After glutathione affinity chromatography and cleaved from GST by factor Xa,the recombinant MTS-αB-C was separated from GST and factor Xa by anion exchange chromatography.Recombinant MTS-αB-C was characterized by SDS-PAGE and Western immunoblot analysis.The purified MTS-αB-C migrated on SDS-PAGE as a single band to an apparent molecular mass (23 ku) that corresponded to total native αB-C and MTS,and was recognized on Western immunoblot by anti-human αB-crystallin antibody. Both MTS-αB-C and GST- MTS-αB-C displayed chaperone like function by disaggregating the denatured and aggregated actin induced by H₂O₂ treatment in an ATP-containing buffer at 37℃.It was observed under fluorescence microscope that FITC-labeled MTS-αB-C had gone into neonatal rat cardiomyocytes by MTS mediation after the cells were incubated with the MTS-αB-C for 8 hours.