|
Angiotensin Ⅰ-converting enzyme (ACE) plays an important role in the regulation of blood pressure, which can promote the degradation of angiotensin II formation and bradykinin, causing high blood pressure. ACE inhibitors has become an important drug for the clinical treatment of hypertension. Leu-Arg-Pro (LRP), and Leu-Lys-Pro (LKP) is a corn protein and fish protein hydrolyzate, and ACE inhibitory activity (IC50) to 0.27μmol / L, and 0.32μmol / L. The design of ACE inhibitory peptides synthesized high activity for the purpose of this article to explore the structure-activity relationship of ACE inhibitory peptide, polypeptide amino acid composition and molecular conformation change of the activity of work. LRP and LKP skeleton based on the structural features of the ACE inhibitory peptide design and synthesis of LRP and LKP 16 ACE inhibitory peptide, study their ACE inhibitory activity and structure by molecular docking analysis inhibitor with the enzyme binding site. By microwave assisted solid phase peptide synthesis method, using 2 - chloro-trityl chloride resin or a Wang resin is a solid phase carrier, the use of an orthogonal protection strategy with Fmoc for the N-terminal α-amino-protecting group of the condensation, HBTU-HOBt reagent, 20% piperidine / DMF to de-protecting reagents, synthesis of 16 sequences of the LRP and LKP its analogs, and the crude product was precipitated by ether and centrifuged, and were characterized by RP-HPLC and ESI-MS. Synthetic sequences in vitro ACE inhibiting activity was measured, and the results showed that in the new design of the 14 sequences, Leu-Arg-Pro-Phe-Phe exhibited the strongest activity of inhibiting ACE, the IC50 is reached 0.26μmol / L, the middle of the sequence Pro emergence can be resistant to in vivo hydrolysis of the protease. LRP for the skeleton of the series, when the C-terminal containing two of the same amino acid residue (-Phe-Phe), the sequence having the highest inhibitory activity, change one of the any one amino acid will lead to decreased activity; to LKP skeleton of the series, when the C-terminal L-Pro sequence having the highest inhibitory activity, followed by the order of D-Pro, Ac6c infer ACE its inhibitor C-terminal amino acid residue has a strong stereospecific . This article by molecular docking study combined with the mode of action of the inhibitor and the ACE, the results showed that in addition to the sequence number 12 and 14, the rest of the synthesis of the ACE inhibitory peptide mainly occupy S1 point and form hydrogen bonds with the Tyr523, Ala356, and Glu403, form a hydrophobic interaction with Phe391 and Val518 to stabilize its conformation. We select the activity the best and worst sequence carried out a detailed analysis of the docking, the formation of hydrogen bonds is also consistent with the experimental results.
|