鲎素抗菌肽分子结构稳定性及生物活性的研究

鲎素是一种高效的、广谱的抗菌肽,已经成为研究热点.为了实现鲎素在生产实践中的应用，研究鲎素在体外分子结构、生物活性的稳定性.本文采用不同温度、pH值、体外蛋白酶(胃蛋白酶、胰蛋白酶、弹性蛋白酶、羧肽酶B )分别处理鲎素.通过检测鲎素最小抑菌浓度(MIC)的变化,来衡量鲎素生物活性稳定性;采用HPLC法检测鲎素残留量,通过HPLC图谱变化来评定鲎素分子结构稳定性情况.结果表明:在t < 120℃、pH < 10.0作用情况下,鲎素对大肠杆菌K88的MIC为1.25～2.5 mg/L,高效液相色谱检测鲎素残留量在65.5～70.2μg之间;鲎素对胃蛋白酶的作用表现出很高的稳定性,对胰蛋白酶、羧肽酶、弹性蛋白酶的作用稍微敏感.在胃蛋白酶浓度小于 320 U/mL,胰蛋白酶浓度小于40 U/mL,羧肽酶浓度小于20 U/mL,弹性蛋白酶浓度小于2.5 U/mL作用下鲎素仍具有活性.通过实验得出结论:鲎素抗菌肽具有较强的高温耐受性,在酸性条件下具有稳定性,同时鲎素具有一定的耐受蛋白酶降解的能力.

Study on the stability of molecular structure and activity of tachyplesin

Tachyplesin has high performance and broad-spectrum bioactivities against Gram positive and Gram negative bacteria, fungi, and some viruses. Nowadays, the study of tachyplesin has become a hot topic. In order to realize the application of tachyplesin in the field of pharmaceutical industry, the molecular structure and antibacterial activity of tachyplesin were investigated in this paper. The stability of the tachyplesin on temperature, pH and four proteinases (trypsin, pepsin , elastase and caboxypeptidaseB) was studied. The stability of antibacterial activity is measured by the change of minimal inhibitory concentration(MIC) against E.Coli K88; The stability of molecular structure was evaluated by the change of peak in HPLC. The residual content of tachyplesin is detected by HPLC, The results indicated that the molecular structure and antibacterial activity of tachyplesin are completely stable under 120℃ or under pH value 10.0. The MIC of tachyplesin against E.Coli K88 are kept constant in value from 1.25 mg/L to 2.5 mg/L, The residual content of tachyplesin is at the range from 65.5 μg to 70.2 μg. With regard to the four proteinases, the results indicated that the tachyplesin is sensitive to trypsin、carboxypeptidase B and elastase, but it is very stable to pepsin. In addition, tachyplesin is stable in solution of pepsin、trypsin、carboxypeptidase B and elastase respectively at concentration under 320 U/mL、40 U/mL、20 U/mL、2.5 U/mL.