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tannase

n. (context enzyme English) Any enzyme that catalyzes the hydrolysis of tannic acid to gallic acid

Wikipedia
Tannase

In enzymology, a tannase is an enzyme that catalyzes the chemical reaction

digallate + HO $\rightleftharpoons$ 2 gallate

Thus, the two substrates of this enzyme are digallate and HO, whereas its product is gallate.

This enzyme belongs to the family of hydrolases, specifically those acting on carboxylic ester bonds. The systematic name of this enzyme class is tannin acylhydrolase. Other names in common use include tannase S, and tannin acetylhydrolase.

In addition to catalyzing the hydrolysis of the central ester bond between the two aromatic rings of digallate ( depsidase activity), tannase may also have an esterase activity (hydrolysis of terminal ester functional groups that are attached to only one of the two aromatic rings).

Tannase is a key enzyme in the degradation of gallotannins, a type of hydrolysable tannins. It is present in a diverse group of microorganisms, including rumen bacteria.