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Title: An in vitro system from maize seedlings for tryptophan-independent indole-3-acetic acid biosynthesis

The enzymatic synthesis of indole-3-acetic acid (IAA) from indole by an in vitro preparation from maize (Zea mays L.) that does not use tryptophan (Trp) as an intermediate is described. Light-grown seedlings of normal maize and the maize mutant orange pericarp were shown to contain the necessary enzymes to convert [{sup 14}C]indole to IAA. The reaction was not inhibited by unlabeled Trp and neither [{sup 14}C]Trp nor [{sup 14}C]serine substituted for [{sup 14}C]indole in this in vitro system. The reaction had a pH optimum greater than 8.0, required a reducing environment, and had an oxidation potential near that of ascorbate. The results obtained with this in vitro enzyme preparation provide strong, additional evidence for the presence of a Trp-independent IAA biosynthesis pathway in plants.
Authors:
 [1] ;  [2] ;  [3]
  1. Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Dept. of Forest Genetics and Plant Physiology
  2. Univ. of Maryland, College Park, MD (United States). Dept. of Plant Biology
  3. Dept. of Agriculture, Beltsville, MD (United States)
Publication Date:
OSTI Identifier:
305473
Resource Type:
Journal Article
Resource Relation:
Journal Name: Plant Physiology (Bethesda); Journal Volume: 119; Journal Issue: 1; Other Information: PBD: Jan 1999
Sponsoring Org:
USDOE, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
55 BIOLOGY AND MEDICINE, BASIC STUDIES; MAIZE; ACETIC ACID; BIOSYNTHESIS; SEEDLINGS; INDOLES; BIOLOGICAL PATHWAYS; ENZYME ACTIVITY