title: Cucumber seedling indoleacetaldehyde oxidase.
abstract: Extracts of light-grown Cucumis sativus L. seedlings catalyzed the oxidation of indole-3-acetaldehyde to indole-3-acetic acid. No added cofactors were required. Inhibitor studies indicated that the enzyme is a metalloflavoprotein. While indole-3-aldehyde, benzaldehyde, and phenylacetaldehyde partially inhibited the oxidation of indole-3-acetaldehyde, suggesting that they may serve as alternative substrates, it is proposed that indoleacetaldehyde is the major substrate in vivo. 2,4-Dichlorophenoxyacetic acid strongly inhibited the indoleacetaldehyde oxidase activity, and it is proposed that this enzyme may be subject in vivo to feedback inhibition by indole-3-acetic acid. The enzyme was activated by brief heating or by treatment with mercaptoethanol.
authors: Biochemistry and Biophysics Section, Biological Sciences Group, University of Connecticut, Storrs, Connecticut 06268.
authors: P J
authors: PJ
authors: Bower
authors: H M
authors: HM
authors: Brown
authors: W K
authors: WK
authors: Purves