双峰驼乳中乳铁蛋白的体外抗菌活性及影响因素

Study on Antibacterial Activity and Its Influential Factor of Lactoferrin in Bactrian Camel Milk in vitro

采用试管二倍稀释法测定了双峰乳中驼乳铁蛋白(CLF)的抗菌活性。结果表明,CLF对大肠埃希菌的最小抑菌浓度(MIC)为3 mg/mL,对金黄色葡萄球菌的最小抑菌浓度为2 mg/mL,与溶菌酶联合应用,则能明显增强其抗菌作用。CLF的抗菌活性还与其铁饱和度密切相关,随着铁饱和度的增加其抗菌活性明显下降。葡萄糖、蔗糖、麦芽糖、牛血清白蛋白(BSA)、尿素和硫酸铵在0 mg/mL^10 mg/mL的质量浓度范围内,对CLF的抗菌活性影响不大。而NaCl或KCl的浓度为25 mmol/L^100 mmol/L,MgCl2或CaCl2的浓度为1.0 mmol/L^5.0 mmol/L时,CLF的抗菌活性则会明显降低。经较低温度加热处理后CLF能很好的保持其活性;而经较高温度加热处理会使CLF变性并失去抗菌活性。不同pH条件下的抗菌试验结果表明,当pH在7.5~8.0时CLF的抑菌效果最好。

The antibacterial activity of CLF was studied by using test tube double dilution method. The MIC of CLF against E. coli and S. aureus were 3 mg/mL and 2 mg/mL, respectively. Combined with lysozyme could strengthen CLF antibacterial activity. CLF antibacterial activity was obviously reduced when its iron saturation increased. Glucose, sucrose, maltose＇ BSA, urea, ammonium sulphate at concentrations of 0 mg/ mL-10 mg/mL had no significant effects on the antibacterial activity of lactoferrin. Its antibacterial activity was reduced in the presence of NaC1 or KCl at concentration of 25 mmol/L-100 mmol/L, MgCl2 or CaCl2 at concentration of 1.0 mmol/L-5.0 mmol/L. The different pH conditions and heat treatment of CLF also had significant influence on its antibacterial activity. The results indicated that CLF was very stable at low temperature,but at high temperature it lost activty. The CLF was most active under slight alkaline（pH 7.5- 8.0）conditions.