In vitro Effect of Oak Tannins on some Hydrolytic and Ammonia Assimilating Enzymes of the Bovine Rumen

Effect of tannin-containing extract of oak (Quercus incana) leaves on rumen urease, cellulase, protease, amylase, glutmate dehydrogenase (both NADH- and NADPH specific), glutmate-pyruvate transaminase, glutamate oxaloacetate transaminase and glutamine synthetase (both r-glutamy 1 transferase and forward reaction) were strolled in vitro. Tennins decreased activities of ail the enzymes except glutamine synthetase, and the inhibition was higher when substrate rather than the enzyme was added for start of the reaction. An activation was observed for glutamine synthetase (both r-glutamyl transferase and forward reaction) by oak tannins. The activation increased upto a certain level of tannins but it decreased at higher concentration of tannins.