Open AccessCucumber Seedling Indoleacetaldehyde Oxidase
Author(s) -
Peter J. Bower,
H. M. Brown,
William K. Purves
Publication year - 1978
Publication title -
plant physiology
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.61.1.107
Subject(s) - phenylacetaldehyde , acetaldehyde , cucumis , indole test , enzyme , chemistry , biochemistry , substrate (aquarium) , benzaldehyde , indole 3 acetic acid , oxidase test , cofactor , seedling , stereochemistry , biology , botany , catalysis , auxin , ecology , gene , ethanol
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.