Abstract:

The effect of tannic acid on the activities of cellulase and xylanase was investigated and the mechanisms were
explored using enzymatic kinetics, ultroviolet spectroscopy and fluorescence spectroscopy. Tannic acid was found to inhibit
both enzymes with an inhibitory rate of 0.5 mg/mL (37.16%) for xylanase and 1.0 mg/mL(35.33%) for cellulase. Kinetic
invesitgations illustrated that taannic acid had competitve inhibition on cellulase, while its inhibition on xylanase was
manifested by improving its affinity but decreasing the reaction rate. UV and fluorescence spectroscopic analyses suggested
that covalent interactions of tannic acid with the aromatic amino acid residues in enzyme molecules formed stable complexes
so as to influence the enzyme reactions.

Key words: tannic acid, cellulase, xylanase, activity