乳铁素B的抗菌活性及其影响因素

乳铁素B是牛乳铁蛋白经胃蛋白酶酶解后得到的最重要的抗菌肽，具有较强抗菌活性．研究表明，乳铁素B对大肠杆菌的最小抑菌质量浓度为0．5mg／mL，对金黄色葡萄球菌的最小抑菌浓度为0．4mg／mL；葡萄糖、蔗糖、麦芽糖、牛血清白蛋白(BSA)、尿素、硫酸铵在0～10mg／mL，乳糖、可溶性淀粉在0～4mg／mL，的质量浓度范围内，对乳铁素B的抗菌活性影响不大；当NaCl或KCl的浓度为25～100mmol／L，MgCl2或CaCl2的浓度为1．0～5．0mmol／L时，乳铁素B的抗菌活性就会大大降低；随着缓冲盐浓度和有机酸浓度(25～100mmol／L)的增大，乳铁素B的抗菌活性呈下降趋势，且在微碱性环境下乳铁素B表现出较强的抗菌活力．

The Antibacterial Activity and Influential Factors of Lactoferricin B

Lactoferricin B (Lfcin-B) is the main antimicrobial peptide generated by pepsin digestion of bovine lactoferrin(BLf). Lfcin-B also shows a significant antibacterial activity than that of lactoferrin. In this paper, the antibacterial activity of Lfcin-B was studied. It was found that the MIC of Lfcin-B repressing E.coli and S. aureus is 0.5mg/mL and 0.4 mg/mL, respectively. Glucose, sucrose, maltose, BSA, urea, ammonium sulphate at concentration 0~10 mg/mL, and lactose, starch at concentration 0~4 mg/mL have no effect on the antibacterial activity of Lfcin-B. The antibacterial effectiveness was reduced in presence of NaCl or KCl at concentration 25~100 mmol/L, MgCl_2 or CaCl_(2 )at concentration 1.0~5.0 mmol/L, or in presence of various buffer salts. The effectiveness declined with concentrations increases of various buffers salts or carboxylic acids within the range of 25 to 100 mmol/L. Furthermore, the protein was most effective under slightly alkaline conditions in each case.