Qualitative and Quantitative Analyses of Sialyl O-Glycans in Milk-Derived Sialylglycopeptide Concentrate

Sialyl glycans have several biological functions. We have previously reported on the preparation and bifidogenic activity of milk-derived sialylglycopeptide (MSGP) concentrate containing sialyl <i>O</i>-glycans. The current study qualitatively and quantitatively analyzed the sialyl <i>O</i>-glycans present in the MSGP concentrate. Notably, our quantitative analysis indicated that a majority of <i>O</i>-glycopeptides in the MSGP concentrate were derived from glycomacropeptides. The concentrate was found to contain mainly three types of sialyl core 1 <i>O</i>-glycans, with the disialyl core 1 <i>O</i>-glycan being the most abundant. We successfully quantified three types of sialyl core 1 <i>O</i>-glycans using a meticulous method that used homogeneous <i>O</i>-glycopeptides as calibration standards. Our results provide valuable insights into assessment strategies for the quality control of <i>O</i>-glycans in dietary products and underscore the potential applications of MSGP concentrate in the food industry and other industries.