Abstract: A rapid and highly efficient method for identifying angiotensin I converting enzyme inhibitory peptides from protein hydrolysates was established based on quantitative structure activity relationship (QSAR) and protein sequence. First, a small peptide library was constructed by protein sequence searching according to the hydrolysis sites of a specific enzyme. Then, the activities of peptides in the library were predicted using QSAR model. Target peptides were synthesized and their IC50 values were measured. Finally, a real protein hydrolysate was prepared and HPLC was employed to analyze the target peptides in the hydrolysates. Totally 34 tripeptides with an IC50 of less than 10 μmol/L were predicted from rapeseed protein, wheat protein and rice protein and 11of them with higher activity were synthesized. LRL with the lowest IC50 of 3.42μmol/L located in rapeseed cruciferin BNC1 (P33523) sequence 347—349 was characterized from the synthesized peptides.

Key words: ACE inhibitor, quantitative structre activity relationship(QSAR), activity prediction, rapeseed protein, wheat protein, rice protein