Carbohydrates play important roles in biological systems and influence cancer metastasis, bacterial and viral infection, cell-cell interactions. Carbohydrates on glycoproteins also affect their structures and functions. We focus on developing novel chemoenzymatic methods that combine the flexibility of chemical synthesis and the high efficiency and superior selectivity of enzyme-catalyzed reactions for elucidating the structure-function relationship of carbohydrates and glycoconjugates. We are also interested in structural and biochemical characterization of glycosyltransferases and other carbohydrate biosynthetic enzymes as well as designing mutants as better catalysts for carbohydrate synthesis. Additionally, developments of effective bioassays, glycosidase inhibitors, and carbohydrate-based diagnostics and therapeutics are ongoing research efforts of the group.