乳铁蛋白水解物修饰物的分离纯化及其抗大肠杆菌活性

摘要

The lactoferrinhydrolysate(LHS) with a minimum inhibitory bacterial concentration of 200 mg/mL was hydrolyzed by pepsin.And then the lactoferrinhydrolysate was modified with tryptophan(Trp)LHS and its tryptophan modifier were separated and purified by Sephadex G-25.The peak products were collected and their antibacterial activity was determined.Especially,the purred peak 1 belong to the antibacterial activity peak and the antibacterial effect of the separative products were LHS ＜ LHS' s peak 1 product ＜ Trp modifier ＜ Trp modifier's peak 1 product.The inhibitory rates of LHS and Trp modifier on Escherichia coli were 40.42％ and 85.83％ at the concentration of 200 mg/mL.When adding the concentration of 100 mg/mL,the inhibitory rates of LHS' s peak 1 product,Trp modifier and Trp modifier's peak 1 product on Escherichia coli were 41.12％,58.31％ and 88.00％,respectively.Then,the inhibition rate of tryptophan modifier against Escherichia coli was 45.41％ higher than its unmodifier.The inhibition rate of tryptophan modifier's purified product against Escherichia coli was 29.69％ higher than its not purified product.The collected products were further separated and identified by reversed-phase high performance liquid chromatography(RP-HPLC).The result demonstrated that the antibacterial peptide with high purity and high activity was obtained by separation and purification.%利用胃蛋白酶水解乳铁蛋白得到最小抑菌浓度为200 mg/mL的乳铁蛋白水解物(LHS),进行类蛋白反应导入色氨酸(Trp)得到乳铁蛋白水解物修饰物.对LHS及其色氨酸修饰产物采用葡聚糖凝胶过滤色谱G-25进行分离纯化,收集出峰产物,比较各级产物的抗大肠杆菌活性.结果表明,LHS和Trp修饰物分离纯化后的峰1为抑菌活性峰,各级产物的抑菌效果为LHS＜ LHS纯化峰1产物＜Trp修饰产物＜Trp修饰产物纯化峰1产物.加样浓度200 mg/mL时,LHS、Trp修饰物对大肠杆菌的抑菌率分别为40.42％和85.83％.加样浓度100 mg/mL时,LHS纯化峰1产物、Trp修饰物、Trp修饰物纯化峰l产物对大肠杆菌抑菌率分别为41.12％、58.31％和88.00％.可见,色氨酸修饰物对大肠杆菌的抑菌率较未修饰前提高了45.41％,色氨酸修饰产物经过纯化后对大肠杆菌的抑菌率较未纯化前提高了29.69％.将收集的活性峰作为样品,采用反相高效液相色谱进一步分离鉴定,证明经过分离纯化得到了纯度相对较高且活性提高的抗菌肽.