高体细胞数低乳糖含量时牛乳清蛋白组分变化的研究

Effect of Somatic Cell Count and Low Lactose in Milk on Changes of Whey Proteome

旨在分析奶牛牛乳中体细胞数升高乳糖含量降低的同时乳清蛋白的表达变化。依据牛乳中体细胞数和乳糖含量,分为高体细胞数低乳糖含量组和正常牛奶组,超速离心分离乳清,采用二维凝胶电泳技术分离了高体细胞数低乳糖和正常牛乳清蛋白,考马斯亮蓝G-250溶液染色,基质辅助激光解析飞行时间质谱检测表达变化的蛋白点。高体细胞数低乳糖含量的牛乳中β酪蛋白含量降低,而白蛋白、结合珠蛋白、乳铁蛋白、转铁蛋白和抗菌肽1等乳清蛋白表达量增加。表明随着牛乳中乳糖含量的降低,乳清蛋白组分表达量增加,这可能是奶牛乳腺在乳糖合成降低时乳腺上皮细胞完整性破坏引起的防御应答。

The aim of the current study was to investigate the changes of the whey protein when the somatic cell count increased and lactose content decreased in milk.Milk was classified into milk with low lactose and high somatic cell count,and control group according to concentration of lactose and somatic cell count in milk.Whey proteins were collected by ultracentrifugation and separated by two-dimensional gel electrophoresis,stained with Coomassie Blue G-250 solution,and identified by matrix assisted laser desorption ionization time of flight mass spectrometry.β-casein was decreased,while whey proteins including serum albumin,haptoglobin,lactoferrin,transferrin and cathelicidin 1 increased in milk with low lactose and high somatic cell count group.The results suggested that the increase of whey proteins in milk was associated with concentration of low lactose,which may be the defense response of mammary gland to the damage of integrity of mammary gland epithelial cells when lactose content decreased in milk.