Large-scale preparation and glycan characterization of sialylglycopeptide from bovine milk glycomacropeptide and its bifidogenic properties

Bovine glycomacropeptide (GMP) is a 7,000-Da glycopolypeptide released from ?-casein during cheese making. The O-glycan chains linked to GMP have many biological activities, but their utilization for nutraceutical products limited due low content. To concentrate the functional glycan of GMP, we prepared sialylglycopeptide (SGC) GMP-containing whey protein via proteolytic digestion peptide and concentration by ultrafiltration using membranes with molecular weight cut-off 1,000 Da. abundant saccharides detected in SGC were N-acetylneuraminic acid (Neu5Ac: 32.3% wt/wt), N-acetylgalactosamine (11.3%), galactose (10.2%), which constitute O-glycans attached GMP. Neu5Ac content was found concentrated at approximately 4.8-fold its (6.8%). Structural analysis O-glycopeptides liquid chromatography tandem mass spectrometry identified 88 O-glycopeptides. Moreover, O-acetylated or O-diacetylated addition previously characterized Quantitative fluorescence labeling chemically revealed that disialylated tetrasaccharide most (76.6% total O-glycan). We further examined bifidogenic properties vitro, served as more potent carbon source than contributes growth-promoting effects on certain species bifidobacteria. Overall, our study findings indicate contains has activity. protocol preparation described herein relatively simple, providing high yield glycan, can be used large-scale preparation.