Purification And Characterization Of Antibacterial Peptides Secreted From Frog (Hylarana Guentheri) In Chongqing

Because drug resistance to pathogenic bacteria has been become serious in therecent years, it is rather impending to search for new antimicrobial drugs from variousnatural sources. Thereby amphibian antibacterial peptides (ABPs) have been givenmuch attention and become an important object for our screening antimicrobial drugsbecause of ABP's special features with small molecular weight, water-solubility andlow antigenicity. In addition, it was found that ABPs have some anti-viral, anti-tumorand hemolytic activities. Based on the discrepancy in their structures they were dividedinto three groups: the linear α-helix peptide, the loop peptide and the peptide whichcontains10to13amino acid residues. So far it has been found that the antimicrobialpeptides existed in multiple families, such as Magainin, Aurein, Bombinin,Bombinin-like and Brevinin family etc. Their different families presented somedifferent antibacterial activitis. ABPs killed microorganism mainly by two mechanisms:lysis or non-lysis of plasma membrane. Besides, ABPs were widely applied intoclinical medicine, food preservation and agriculture. In this paper, from the skinsecretions of frog (Hylarana guentheri) collected in Chongqing the antimicrobialpeptides were isolated, purified and characterized, including: through two-stepchromatography (HPLC C-18and C-4column) the antimicrobial peptides A and Bwere obtained, which both presented only one peak, which concentrations respectivelywere1.115mg/ml and1.955mg/ml, which exhibited good stable to temperature,acidity, metal ions and some proteinase inhibitors, and which have good antibacterialactivities for staphylococcus aureus, bacillus subtilis, pseudomonas aeruginosa,escherichia coli, and which also effectively kill saccharomyces cerevisiae in theirconcentrations up to13μg/ml and24μg/ml, respectively, but not penicillium, whichhave no trypsin hydrolysis activity, trypsin inhibitor activity and blood coagulationactivity, anticoagulant activity but slight fibrinolytic activity. Antimicrobial peptide Ahas no hemolysis activity but peptide B has mild activity. The hemolysis rate ofPeptide B was50%when its concentration was more than154μg/ml.