牛乳与山羊乳中乳桥蛋白的比较研究

Comparative study of lactopontin in cow milk and goat milk

山羊乳是近年来备受瞩目的动物乳源,含有在婴儿早期发育中发挥多种生物活性的乳源性骨桥蛋白(osteopontin,OPN),也被称为乳桥蛋白(lactopontin,LPN),但目前关于山羊乳LPN的研究还较少,对于其结构特点及与牛乳LPN的差异还未见相关报告。通过对山羊乳和牛乳中LPN进行序列相似度分析,并进行富集和测定,比较两者在磷酸化修饰的差异,探讨山羊乳LPN与牛乳LPN结构的异同。结果显示,山羊乳和牛乳LPN完全相同的氨基酸比例高达90.94%,并且均存在同样的整合素蛋白结合序列。山羊乳LPN未鉴定到O-糖基化修饰,山羊乳LPN和牛乳LPN的磷酸化修饰位点基本一致,但同一位点的磷酸化修饰位点覆盖率在两者间略有差异。结果说明,山羊乳LPN可能具有与牛乳LPN相似的生物活性。

Goat milk is a high-profile animal milk source in recent years,containing a variety of biological activities in early infant development of the milk-derived osteopontin(OPN),also known as lactopontin(LPN),but there are still few studies on goat milk LPN,and there are no relevant reports on its structural characteristics and differences with cow’s milk LPN.In this study,the similarities and differences between LPN and LPN in goat milk were discussed by analyzing the similarity of LPN in goat milk and cow milk,and comparing the differences in phosphorylation modification between the two by enrichment and assay.The results showed that the exact same amino acid ratio of goat milk and cow milk LPN was as high as 90.94%,and the same integrin binding sequence was present.O-glycosylation site was not identified in goat milk LPN.The phosphorylation modification sites of goat milk LPN and cow milk LPN are basically the same,but the phosphorylation modification site occupancy of the same site is slightly different between the two.These results suggest that goat milk LPN may have a biological activity similar to that of bovine milk LPN.