Auxin biogenesis: subcellular compartmentation of indoleacetaldehyde reductases in cucumber seedlings.

  title={Auxin biogenesis: subcellular compartmentation of indoleacetaldehyde reductases in cucumber seedlings.},
  author={Peter John Bower and Hugh M. Brown and William K. Purves},
  journal={Plant physiology},
  volume={57 6},
Subcellular fractionation of cucumber (Cucumis sativus L.) seedlings was achieved, and two of the enzymes in the auxin biosynthetic pathway were localized. NADH-specific indoleacetaldehyde reductase activity was observed only in the cytosol fractions obtained from separated hypocotyl and cotyledon tissue. In contrast, a portion of the NADPH-specific indoleacetaldehyde reductase activity was associated with a microsomal fraction derived from these tissues. The NADPH-specific indoleacetaldehyde… 
Indoleacetaldehyde Reductase of Cucumis sativus L: KINETIC PROPERTIES AND ROLE IN AUXIN BIOSYNTHESIS.
Under certain conditions with NADPH as co-substrate, the enzyme showed kinetics sigmoidal with respect to indoleacetaldehyde concentration and was strongly inhibited by high concentrations of NADPH, suggesting that this substrate inhibition of the NADPH-linked indole acetaldehyde reductase activity by NADPH may function in the regulation of auxin biosynthesis.
Cucumber Seedling Indoleacetaldehyde Oxidasel
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
Indoleacetaldehyde in Cucumber Seedlings 1
The presence of indoleacetaldehyde in cucumber (Cucumis sativus L.) cotyledons was demonstrated by thin layer chromatographic RF values in three solvent systems, by the formation and hydrolysis of a
Indoleacetaldehyde Reductase of Cucumis sativus
The occurrence of multiple IAAld reductases, each specific for a particular pyridine nucleotide, distinguishable with respect to several properties is suggested, supporting the view that the rate of auxin biosynthesis is subject to regulation.
Tryptophan aminotransferase and tryptophan dehydrogenase activities in some cell compartments of spinach leaves: The effect of calcium ions on tryptophan dehydrogenase
The content of spinach-leaf cells was compartmented by differential centrifugation and enzyme activities of L-tryptophan aminotransferase (TAT) and TDH were demonstrated in all cell fractions, with the highest activities of both enzymes found in the pellet of organelles followed by the enzyme activities in the chloroplasts.
Proposed Enzymes of Auxin Biosynthesis and Their Regulation III. Some Properties of Pea Indolylacetaldehyde Oxidase
The pea enzyme seems not to be a dismutase since indolylmethanol or indolylethanol were not formed as products and Pyridine nucleotide coenzymes did not activate the partially purified enzyme.
Indole‐3‐ethanol oxidase in Phycomyces blakesleeanus. Is indole‐3‐ethanol a “storage pool” for IAA?
The observed variations in IEt content were strongly correlated with certain developmental stages of the fungus, and the decrease of IEt between 60 and 84 h of fungal development coincides with a high IEt oxidase activity.
Indole-3-Ethanol Metabolism and Its Possible Role in the Regulation of Indole-3-Acetic Acid Biosynthesis
Indole-3-ethanol was discovered by Ehrlich in 1912, as a metabolite of tryptophan added to yeast cultures, and given the trivial nametryptophol, and contains the same C-N backbone as IAA.
Compartmentation of indole-3-acetic acid metabolism in protoplasts isolated from leaves of wild-type and IAA-overproducing transgenic tobacco plants
Monitoring of cellular compartmentation in protoplasts isolated from sterile wild-type tobacco SRI plants and in IAA-overproducing plants expressing the Agrobacterium tumefaciens T-DNA IAA genes suggests the presence of two differentially subcellular pools of IAA.
Formation of Tryptophol Galactoside and an Unknown Tryptophol Ester in Euglena gracilis.
The unicellular alga Euglena gracilis Klebs ;Z' converted exogenous indole-3-ethanol (trytophol) to two major metabolites: tryptophol galactoside and an unknown compound, and to minor amounts of


Multiple amine oxidases in cucumber seedlings.
Cell-free extracts of cucumber seedlings were found to have amine oxidase activity when assayed with tryptamine as a substrate, and studies of the effect of lowered pH on the extract indicated that this activity was heterogeneous, and threeAmine oxidases could be separated by ion exchange chromatography.
Isolation of Indole-3-ethanol Oxidase from Cucumber Seedlings.
An enzyme is isolating from cucumber seedlings which catalyzes the oxidation of IEt to indole-3-acetaldehyde (IAAld), which has nearly maximum activity from pH 8 to 11 and appears to be reduced to H(2)O(2).
Indole-3-ethanol Oxidase: Kinetics, Inhibition, and Regulation by Auxins.
The results may be interpreted as showing that IAA is a noncompetitive inhibitor which binds to that conformation of the enzyme which also binds indoleethanol, and the significance of these interactions for the regulation of IAA biosynthesis is discussed.
Isolation of Plastids from Sunflower Cotyledons during Germination.
Changes in isopycnic density of plastids on sucrose density gradients are consistent with changes in the plastid ultrastructure caused by the protein-rich prolamellar body or by the lipid-rich thylakoids.
During a study of the inactivation of IAA in aqueous solutions, it was frequently necessary to assay at one time many samples where the IAA concentrations were low, or where the degree of significance of small differences in concentrations between experimental unite required evaluation, so it was desirable to re-examine the ferric chloride-sulphuric acid procedure.
It is only with onion that the Golgi apparatus has been isolated in a form that would warrant further purification for biochemical analysis, and by utilizing this procedure, it has been possible to obtain fractions of Gol Gi apparatus from plant tissues other than onion stem.