摘要
乳铁蛋白对G-和G+都有抑菌效果,乳铁蛋白对G-的作用比较强。铁饱和度越低,抑菌性越强。环境pH值变化对G-影响不大,对G+影响较大,pH为7.5～8.0时抑菌效果最佳。乳铁蛋白经过70℃以下的巴氏杀菌后抑菌活性没有影响。HCO3-浓度增加,有利于增强抑菌性。柠檬酸盐和阳离子浓度增加会使抑菌活性下降。圆二色性分析表明,随着铁饱和度的增加,乳铁蛋白的α-螺旋构象逐步转变为β-折叠构象,蛋白质分子排列更为有序,分子的结构变得更加紧密。DSC研究表明乳铁蛋白的N-叶和C-叶铁结合能力不同造成热稳定性差异,低铁饱和度时较高的抑菌活性主要来自于C-叶。
Lactoferrin （LF） shows antimicrobial activity on both Gram-negative and Gram-positive bacteria, especially the former. The antimicrobial effect improves with decrease of the iron saturation decreases. The change in pH values could affect the inhibition capability of Gram-positive bacteria but not of Gram-negative strains, while the optimum antibacterial effects are found to be pH 7.5-8.0. The bacteriostatic effects increase with higher concentration of bicarbonate, but decrease with addition of citrate and cation. Circular dichroism （CD） analysis of the secondary structure of LF showed that α-helix is transformed to β-sheet with increase of iron saturation, and the arrangement of molecular becomes better arranging in order and the structure of protein becomes more compact. DSC results indicated that the difference in the heat sensitivity between N-lobe and C-lobe is caused by the difference of the iron-binding capacity of the two lobes. The higher antibacterial activity with less ironsaturation is resulted from C-lobe.
出处
《食品科学》
EI
CAS
CSCD
北大核心
2008年第2期238-243,共6页
Food Science
基金
国家"863"计划项目(2007AA10Z320)
江南大学校预研项目(2004LYY028)
关键词
乳铁蛋白
抑菌活性
铁饱和度
圆二色性
lactoferrim antimicrobial activity
iron saturation
circular dichroism
