Abstract
Activity of indoleacetic acid oxidase in partially purified extracts from cotton is stimulated by small amounts of malate, succinate, fumarate, and other plant acids. The stimulation is apparently due to inhibition of catalase, which is detectable in certain preparations. The lag phase of indoleacetic acid oxidation by crude preparations is eliminated by steps in processing which conceivably either denatures or dilutes catalase, or concentrates inhibitors to catalase.