On the other hand, _-d-glucosidases and _- d-xylosidases were less sensitive to the presence of condensed tannins. In only a fewcases, condensed tannin additions reduced the activity of these enzymes by 50%; in numerous situations, tannin concentrations in excess of 100 _gml−1 were needed for a50%reduction in enzyme activity. Although not readily evident in the figures presented here, at similar concentrations of soluble tannins, _-d-glucosidasewas less inhibited than _-d-xylosidase