Casein was purified from bovine milk by the method of isoelectric precipitation, αs-casein was isolated from casein according to the character that be dissolved in urea solution and αs1-casein was separated with αs2-casein by anion-exchange chromatography. αs1-casein was conjugated with galactooligosaccharide by maillard reaction under certain conditions. Antigenicity of the conjugates was measured by competitive ELISA assay. Results showed the Kd (dissociation constant of antigen-antibody) of the conjugates was increased to 3.7 times compared with αs1-casein and antigenicity of αs1-casein was decreased significantly by conjugation with galactooligosaccharide. Results of animal experiments and noncompetitive ELISA assay indicated that the immunogeniciity of αs1-casein was reduced 19％ by combining with galactooligosaccharide. Results showed that the treatments of conjugation with saccharides had significant effect on the reducing of the antigenicity and immunogenicity of bovine milk αs1-casein and provided scientific basis for developing ideal and practice desensitization production technology of milk.%用等电点沉淀法从牛乳中提取酪蛋白,根据αs-酪蛋白对尿素溶液溶解特性从酪蛋白中提取αs-酪蛋白,并用阴离子交换层析使αs1-酪蛋白与αs2-酪蛋白分离.用低聚半乳糖通过在一定条件下的美拉德反应对αs1-酪蛋白进行糖基化处理,通过竞争ELISA实验检测αs1-酪蛋白糖基化产物的抗原性.结果表明,该糖基化产物的抗原抗体结合常数Kd较αs1-酪蛋白上升3.7倍,即低聚半乳糖糖基化处理使αs1-酪蛋白的抗原性得到显著降低.用动物实验和非竞争ELISA实验检测αs1-酪蛋白糖基化产物的免疫原性,结果显示免疫原性降低19%,该实验证实对降低牛乳αs1-CN抗原性和免疫原性具有显著效果,为开发较理想的、切实可行的新脱敏奶粉生产技术提供了科学依据.
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