Isolation,identification and activity evaluation of ACE inhibitory peptides from Urechis unicinctus
Objective Urechis unicinctus was used as raw material to prepare ACE inhibitory peptides with hypotensive potential by enzymatic hydrolysis and modern separation and purification techniques.ACE inhibitory activity was used as screening index.Methods The inhibition rate of ACE was used as the screening index,and controlled enzymatic hydrolysis technology was used to optimize the conditions of enzymatic hydrolysis.A series of separation,purification and identification techniques including ultrafiltration,Sephadex G-15 gel column chromatography,reversed phase high performance liquid chromatography(RP-HPLC)and mass spectrometry sequencing were used to prepare bioactive peptides with ACE inhibitory activity,and the inhibitor types were determined by Lineweaver-Burk method.Results The optimum conditions were trypsin,37 ℃,pH 8.0,4.0％enzyme dosage,1:30 feed-liquid ratio and 4.0 h enzymolysis time.Five active peptides were isolated,purified and identified as Pro-Gln-Met-Thr-Phe(DHCY1,622.75 Da),Pro-Tyr-Phe-Lys-His(DHCY2,690.8 Da),Pro-Gly-Trp-Lys-Ala(DHCY3,557.66 Da),Pro-Gln-Gly-Met-Ile-Val-Val(DHCY4,742.94 Da)and Val-Met-Arg-Ile-Ile(DHCY5,630.86 Da)by mass spectrometry and amino acid sequence analysis.Amongthem,DHCY1,DHCY4 and DHCY5 showed better ACE inhibitory activity,and the inhibitory rates were(86.26±0.85)％,(92.11±1.13)％and(96.51±1.04)％,respectively.DHCY5 were judged to be a competitive ACE inhibitor.Conclusion The trypsin hydrolyzes Urechis Unicinctus proteins could produce peptides with significant ACE inhibitory activity,including ACE competitive inhibition,which has potential antihypertensive activity,it could provide the theoretical basis and reference for the exploitation and utilization of U.unicinctus enzymatic peptides and the development of antihypertensive products.
Urechis unicinctushydrolyzed peptidesACE inhibitory activityisolation and purification
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