驼乳和牛乳乳清蛋白抑菌肽的分离纯化及抑菌活性的比较

Isolation and Purification of Whey Protein Antibacterial Peptides from Camel and Cow Milk and Comparison of Its Antibacterial Activity

本文以驼乳和牛乳的乳清蛋白为原料,经胃蛋白酶水解后,通过超滤及葡聚糖凝胶层析对其水解物进行分离纯化,其后对获得的蛋白肽进行抑菌活性、二喹啉甲酸法(BCA)蛋白浓度、相对分子质量及氨基酸组成的测定。结果表明:经超滤获得的驼乳和牛乳分子量<3 kDa的多肽片段-F3具有最强的抑菌活性,将F3(<3 kDa)组分通过层析处理得到的驼乳G-25-2和牛乳G-25-2抑菌肽纯度较高(BCA蛋白浓度分别为95.60%和95.32%);驼乳G-25-2和牛乳G-25-2组分对大肠埃希氏菌和金黄色葡萄球菌均有抑菌作用,最小抑菌质量浓度分别均为32.50和65.00 mg/mL;氨基酸分析结果显示,高活性抗菌肽中的总碱性氨基酸和总疏水性氨基酸含量最高,驼乳G-25-2中分别为32.80%和65.76%,牛乳G-25-2中分别为31.77%和58.70%。本研究结果表明,驼乳与牛乳均具有抑菌效果,且其抑菌能力高于牛乳,为今后研究驼乳抑菌肽的深入研究提供理论参考。

Bactrian camel milk and whey protein of cow milk were hydrolyzed by pepsin.The hydrolysate was separated and purified by ultrafiltration and dextran gel chromatography.Bacteriostatic activity,concentration of protein tested by bisquinoline carboxylic acid method(BCA),the relative molecular mass,and the amino acid composition of the obtained protein peptide were determined.The results showed that the polypeptide fragment(F3)of the molecular weight<3 kDa of camel milk and cow milk obtained by ultrafiltration,had the strongest antibacterial activity,the purity of camel milk G-25-2 and cow milk G-25-2 components obtained by chromatography of the F3(<3 kDa)component was higher(protein concentrations were 95.60%and 95.32%,respectively);camel milk G-25-2 and cow milk G-25-2 components had antibacterial activity against Escherichia coli and Staphylococcus aureus,and the minimum inhibitory concentration was 32.50 and 65.00 mg/mL respectively.Amino acid analysis showed that the content of total basic amino acid and total hydrophobic amino acid in the high activity antimicrobial peptide was the highest,32.80%and 65.76%respectively in camel milk G-25-2,and 31.77%and 58.70%respectively in cow milk G-25-2.The research result showed that camel milk and cow milk had similar antibacterial effect and the ability was higher than cow milk,which provided a theoretical reference for further research on camel milk bacteriostatic peptide.