At the Laboratory of Enzymology, we explore the “relationship between the structures and functions” of enzyme molecules and utilize the results in our applied researches. In particular, we focus on carbohydrate-related enzymes involved in the process of degradation and synthesis of carbohydrates to clarify the structure factors (amino-acids and sequences) that activate the enzymes’ characteristic functions through protein engineering techniques. Modification of structure factors is crucial in enabling the composition of highly valuable enzyme molecules and production of new and useful oligosaccharides, megalosaccharides, and polysaccharides. These new types of carbohydrates can be utilized as food materials, functional materials, or nanomaterials in food, medical, and cosmetic industries.