Abstract:The hydrolysis process of soybean protein by subtilisin protease was investigated to explore the peptide mapping changes during this process.High performance liquid chromatography-electrospray quadrupole timeof-flight mass spectrometry was adopted to test hydrolyzation polypeptide in different time periods and investigate the polypeptide sequence and components based on a non-specific peptide mapping identification method.Therefore，the dynamic changes of peptide mapping during enzymatic hydrolysis were revealed.The results indicated that subtilisin protease had a preference for the C-terminal of Histidine and Aspartic and the N-terminal of Threonine and Alanine.