ACTIVATION OF PLANT ACID-PHOSPHATASES BY OXIDIZED GLUTATHIONE AND DEHYDROASCORBATE

An acid phosphatase that was partially purified from spinach leaves was activated by oxidized glutathione or dehydroascorbate. Activation was accompanied by a change in the pH optimum so that the enzyme became active in the neutral as well as in the acid region. At neutral pH, the activation induced by oxidized glutathione was reversed by reduced glutathione. Similar results were obtained with a commercial preparation of potato tuber phosphatase. The results suggest that oxidized glutathione and dehydroascorbate serve not only in the previously demonstrated deactivation of thioredoxin-linked enzymes but also in the activation of other enzymes from plants. © 1979.