An in vitro system from maize seedlings for tryptophan-independent indole-3-acetic acid biosynthesis
- Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Dept. of Forest Genetics and Plant Physiology
- Univ. of Maryland, College Park, MD (United States). Dept. of Plant Biology
- Dept. of Agriculture, Beltsville, MD (United States)
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.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- OSTI ID:
- 305473
- Journal Information:
- Plant Physiology (Bethesda), Vol. 119, Issue 1; Other Information: PBD: Jan 1999
- Country of Publication:
- United States
- Language:
- English
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