EFFECTS OF ACIDIC AND ALKALINE TREATMENTS ON TANNIC-ACID AND ITS BINDING PROPERTY TO PROTEIN

Effects of acidic and alkaline treatments on tannic acid (TA), one of the hydrolyzable tannins, and its binding property to protein [bovine serum albumin (BSA)] were investigated. Dissociation of TA-BSA complex es was apparent in both highly acidic (pH <3) and alkaline (pH >7) tre atments. TA dissociated from the complexes and pure TA was not signifi cantly hydrolyzed in highly acidic (pH 1.0-3.0) media and retained its protein-binding property. TA did not seem to be hydrolyzed even with a more acidic treatment (in 1 M HCl, pH <0.5), although its protein-bi nding property was much reduced. The higher pH treatment (pH >6.5) fac iliated the hydrolysis of TA, as judged by the release of its constitu ent gallic acid.