Activation and Inhibition of Indoleacetic Acid Oxidase Activity from Peas

Abstract
The inhibition of indoleacetic acid oxidase activity by chlorogenic acid is markedly variable. Aqueous extracts of acetone precipitates from etiolated pea epicotyls contain heat-stable substances which decrease the inhibition produced by chlorogenic acid and also have a small activating effect. Low concentrations of pcoumaric acid (1 µ/ml) can stimulate this action. The possible role of activators and inhibitors in the in vivo regulation of indoleacetic acid oxidase activity is discussed.