Chiral medicines selectively interact with biological macromolecules through strict chiral recognition and demonstrate different pharmacokinetic characteristics and drug effects.Two propranolol (PRO) enantiomers (R(+)/S(-)-PRO),nonselective β-adrenergic receptor (β-AR) antagonists,were used to treat the human umbilical vein endothelial cell（HUVEC）.The total proteins from treated cells were extracted and separated by two-dimensional gel electrophoresis (2-DE),the acquired images were analyzed using PDQuest software.A total of 22 differentially expressed proteins were identified by matrixassisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS).10 of them were identified following SWISSPROT database queries,which are HSP86,HSP84,GRP75,KLC18,KBTB2,TGM2,GBLP,GCNT2,RAB36 and KLH34.The data indicated that PRO enantiomers could introduce extensive changes in gene expressions in signaling molecules,metabolic enzymes,skeleton proteins,chaperonin proteins and so on,which might be specific to the chiral characteristics of PRO.Further studies would focused to clarify the roles of several candidate channels and the possible mechanisms involved in the functions of chiral PRO enantiomers.Our results demonstrated that proteomics approaches could provide new strategies for the deeper understanding of chiral drugs and their biological characteristics,which might be significant to improve the development and rationalized clinical administration of chiral drugs.