The effect of l-ascorbic acid on the in vitro activity of polyphenoloxidase from potato

Abstract
The effect of ascorbic acid and its oxidation products on the activity of potato polyphenoloxidase was studied using a modified colorimetric procedure. The enzyme undergoes a marked denaturation in the presence of ascorbic acid which is not reversed by ionic Cu. Cu ions catalyze the rate of formation of colored condensation products from o-benzoquinone. Previous work on polyphenoloxidase systems is discussed in the light of these findings.