Structural diversity of carbohydrate esterases

Carbohydrate esterases (CEs) catalyze the de-O or de-N-acylation by removing the ester decorations from carbohydrates. CEs are currently classified in 15 families in the Carbohydrate-Active Enzyme (CAZy) database, which classifies a large variety of enzymes that assemble, modify and breakdown carbohydrates and glycoconjugates. CEs have significant importance as biocatalysts in a variety of bioindustrial processes and applications. Thus, the understanding of molecular mechanisms involved in CE catalysis is essential. However, despite a rather large number of enzymes classified as CEs, just a few have been studied biochemically and only a handful has their three-dimensional structures determined and analyzed. Here, we present a brief overview of all currently classified CE families, mainly focusing on the structures and enzymatic activities of CEs.