Glycoproteomic profile in wine: a 'sweet' molecular renaissance

Glycoproteins are believed to be important in several technological, oenological and allergological processes due to their physicochemical properties. The knowledge of the protein glycosylation status in wine will aid in the understanding of these processes. A multiplexed glycopeptide enrichment strategy in combination with tandem mass spectrometry was performed in order to analyze the glycoproteome of white wine. A total of 28 glycoproteins and 44 glycosylation sites were identified. The identified glycoproteins were from grape and yeast origin. In particular, several glycoproteins derived from grape, like invertase and pathogenesis-related (PR) proteins, and from the yeast, were found after the vinification process. Bioinformatic analysis revealed sequence similarity between the identified grape glycoproteins and known plant allergens. This study is an important step forward in order to investigate the implication of glycoproteins in several processes, like protein stabilization and potential allergenic cross-reactivity in wine.