Introduction
Carbohydrate esterases catalyze the de-O or de-N-acylation of substituted saccharides. Since an ester = acid + alcohol, we consider two classes of substrates for carbohydrate esterases : those in which the sugar plays the role of the "acid", such as pectin methyl esters and those in which the sugar behaves as the alcohol, such as in acetylated xylan. A number of possible reaction mechanisms may be involved : the most common is a Ser-His-Asp catalytic triad catalyzed deacetylation analogous to the action of classical lipase and serine proteases but other mechanisms such as a Zn2+ catalyzed deacetylation prevails in some families.
The CAZy database provides an updated list of the Carbohydrate Esterase families.