Screening Of Novel Ace Inhibitory Peptides From Sericin Source And Inhibition Mechanism Study

The aim of this paper to screen the ACE inhibitory peptide from sericin hydrolysate and the works included three parts:（1）Main contents are to optmize the silk degumming process.（2）screening the ACE inhibitory peptide from sericin hydrolysate by coupling in silico and in vitro approaches.（3）preliminary screening ACE inhibitory peptide from sericin hydrolysate by selective adsorption of hypercrosslinked polymers with different hydrophobicity.The main research as follows:（1）The results of study that sericin was extracted from silkworm cocoon autoclaving at 121℃,0.2 MPa and 1:30（solid-liquid ratio）for 2 h and the protein content of sericin up to 96.8%.（2）The hydrolysate of Sericin with high ACE inhibitory activity were screened by coupling in silico proteolysis and in vitro approaches.Based amino acids at the C-terminal end usually contribute significantly to ACE-I inhibitory activity,building QSAR model predicted results indicated that the ACE inhibitory activity of these sericin hydrolysate peptides and synthesized peptides exhibited 75%of similar tested log IC₅0 value to predicted one with small prediction errors（<0.7）,which achieved rapid and high-throughput screen.Moreover,the highest ACE inhibitory peptide（SSR）and the lowest ACE inhibitory peptide（SSK）among the chosen six peptides,which were selected for ACE inhibition mechanism analysis which based on Lineweaver-Burk plots indicated that they behave as competitive ACE inhibitors.Molecular docking suggest that the C-terminal residues of short-chain peptides that contain more H-bond acceptor groups could easily form hydrogen bonds with ACE and have higher ACE inhibitory activity.That is why SSR have more higher ACE inhibitory activity compared to SSK.（3）preliminary screening ACE inhibitory peptide from sericin hydrolysate by selective adsorption of hypercrosslinked polymers（HCP-Ben,HCP-Th and HCP-Py）with different hydrophobicity.The results of adsorption experiments shows:After adsorbed by HCP-Ben at 48 h,the ACE inhibitory activity was increased and the IC₅0 value change from 49.98 mg/L to 37.04 mg/L;after adsorbed by HCP-Th and HCP-Py at 48 h,the ACE inhibitory activity was reduced and the’ IC₅0 value change from 49.98 mg/L to 80.40 mg/L and 60.64 mg/L,respectively.That’s achieve preliminary screening and make a good theoretical’ basis for the further purification separation.