ABSTRACT
Figure 4.2 Neuraminidase from influenza virus and its inhibitors developed for use in antiviral medicine. (A) Structure of the substrate of influenza neuraminidase. The arrow indicates the position of the hydrolysis reaction. (B) Zanamivir (Relenza®). (C) Oseltamivir (Tamiflu®).GHs have various modes of action. Henrissat et al. classified GHs on the basis of the similarity of their amino acid sequences, and summarized them in the Carbohydrate Active Enzymes (CAZy) database (https://www.cazy.org/) (Cantarel et al., 2009). In this database, GHs are categorized into 115 families (of which 6 families have been deleted and 109 families remain) on December 1, 2009. GH families show wide structural diversity, and are grouped into 14 clans. A clan is a group of families showing significant similarity in 3-D structure, the conservation of catalytic residues, and the catalytic mechanism (Henrissat et al., 1996). In contrast, GTs can be categorized into only two clans.
