Abstract: IsCT was a non-cell-selective antimicrobial peptide isolated from the scorpion.In order to be used in animal feed,[HT5] [HT5"]it was necessary to study the effects on inhibiting and killing common pathogenic bacteria. Agar gel diffusion and dilution methods were used in this experiment to study the antibacterial activities and stabilities of [L⁶,K¹¹]-IsCT which was the derivative of IsCT. The results indicated that [L⁶,K¹¹]-IsCT had better antibacterial activities to Escherichia coli than Staphylococcus aureus. The minimal inhibitory concentration (MIC) of Escherichia coli was 50 μg/mL. When treated with 121 ℃ 0.12 MPa for 30 minutes or 2.0≤pH≤11.0 for 30 minutes and incubated in artificial gastric juice for 2 h,[L⁶,K¹¹]-IsCT remained excellent antibacterial activities. Therefore,[L⁶,K¹¹]-IsCT presented excellent heat stablility and could resist to extreme pH environment as well as artificial gastric juice.

Key words: antimicrobial peptides; derivative; [L⁶,K¹¹]-IsCT; antibacterial activities; stablility