The College of Life Sciences, Northwest University, Xi'an 710069, China.
Shaanxi Natural Carbohydrate Resource Engineering Research Center, College of Food Science and Technology, Northwest University, Xi'an 710069, China.
Carbohydr Polym. 2022 Feb 15;278:118918. doi: 10.1016/j.carbpol.2021.118918. Epub 2021 Nov 19.
Yak milk (YM) has higher protein content than other bovine milk (BM) varieties. The bioactivity of milk glycoproteins is related to N/O-glycans. We qualitatively and quantitatively compared the N/O-glycome of YM and BM glycoproteins using stable isotope labeling combined with hydrophilic interaction chromatography and electrospray ionization mass spectrometry. We identified 79 and 78 N-glycans in YM and BM, respectively. Two N-glycans (H4N5F1A1; H5N4F1) were exclusive to YM. The content ratios of different types of N-glycans differed significantly between YM and BM, with sialylated N-glycans 2.33 times more abundant in YM. Five and seven O-glycans were detected in YM and BM, respectively. Two O-glycans (H1N2; H1N2A1) were exclusive to BM. The bi-sialylated O-glycan, H1N1A2, accounted for 56.1% of O-glycans in YM; it was 5.97 times more abundant in YM than in BM (equal volume basis). This study provides a theoretical basis for the future utilization of YM as a functional food.
牦牛奶（YM）的蛋白质含量高于其他牛乳（BM）品种。乳糖蛋白的生物活性与 N/O-聚糖有关。我们使用稳定同位素标记结合亲水相互作用色谱和电喷雾电离质谱，定性和定量比较了 YM 和 BM 糖蛋白的 N/O-聚糖组。我们分别在 YM 和 BM 中鉴定出 79 和 78 个 N-聚糖。两种 N-聚糖（H4N5F1A1；H5N4F1）是 YM 所特有的。YM 和 BM 中不同类型的 N-聚糖含量比例差异显著，其中 YM 中的唾液酸化 N-聚糖含量是 BM 的 2.33 倍。在 YM 和 BM 中分别检测到 5 种和 7 种 O-聚糖。两种 O-聚糖（H1N2；H1N2A1）是 BM 所特有的。双唾液酸化 O-聚糖 H1N1A2 占 YM O-聚糖的 56.1%；它在 YM 中的丰度是 BM 的 5.97 倍（以相等体积为基础）。本研究为未来将 YM 作为功能性食品的利用提供了理论基础。
