Isolation,Purification And Activity Analysis Of Antimicrobial Peptide BSN27 From Bovine Spleen

Antimicrobial peptides(AMPs)are widely distributed in the body,can inhibit bacteria,fungi,protozoa and certain viruses and are a class of small molecules(<10k Da)peptides.Mammalian spleen has a variety of biological functions,including participating inimmune response of the body.The aim of this study was to isolate and purify new antimicrobial peptides from the spleen of Holstein bovine,and to detect the antibacterial activity of the isolated peptides.In this study,the spleen of bovine was obtained by aseptic technique,and the spleen extract was obtained by tissue homogenate,ultrasonic disruption,acetic acid extraction and high-speed centrifugation.The peptide was isolated and purified with cation exchange chromatography and reverse high performance liquid chromatography(RP-HPLC).Escherichia coli(ATCC8099)and Staphylococcus aureus(ATCC6538)were used as the indicator of the antibacterial activity test to obtain an antibacterial peptide with strong antibacterial activity.The amino acid sequence of the isolated peptide was obtained by MALDI-TOF-MS mass spectrometry and sequence alignment analysis.The results acquired with the analysis of APD3 antimicrobial peptide database showed that BSN27 had 27 amino acid residues,consisting of 5 kinds of amino acids,valine(Ile,I)accounted for 14%(4),phenylalanine(Phe,F)%(3),proline(Pro,P)accounted for 51%(14),tyrosine(Tyr,Y)accounted for 3%(1),arginine(Arg,R)accounted for 18%(5).The net charge is +5.The total hydrophobicity is 25%.The GRAVY is-0.7333,indicating that it is a hydrophilic polypeptide.Because of the high content of proline(P),BSN27 may be an antimicrobial peptide.The homology of BSN27 with antimicrobial peptides Bac5,New Zealand deer P9,sheep Oa Bac5,goat Ch Bac5 and porcine SP-B were 62.79%,60%,55.81%,53.48% and 50%,respectively.The antibacterial activity of bovine spleen antimicrobial peptide BSN27 was detected with synthesized peptide.The results showed that the antimicrobial peptide BSN27 had a good antibacterial effects against Escherichia coli(ATCC8099)and Staphylococcus aureus(ATCC6538).