Mechanism of corn indole-3-acetic acid oxidase in vitro

BeMiller, James N.; Colilla, William

doi:10.1016/s0031-9422(00)89828-3

Cited by 34 publications

(25 citation statements)

References 37 publications

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“…The ready interconvertibility of indole-3-carboxaldehyde and indole-3-methanol, however, makes it difficult to decide which compound is the primary indolyl-C, metabolite. While an aldehyde would be a common product of an oxidative chain-cleaving reaction, parallel formation of both alcohol and aldehyde via 3-methyleneindolenine has also been proposed (1).…”

Section: Methodsmentioning

confidence: 99%

Metabolism of Tryptophan, Indole-3-acetic Acid, and Related Compounds in Parasitic Plants from the Genus Orobanche

Magnus¹,

Šimaga²,

Iskrić³

et al. 1982

Plant Physiol.

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Metabolic reactions involving the aliphatic side chain of tryptophan were studied in the holoparasitic dicotyledonous plants Orobanche graciis Sm., 0. haea Baumg., and 0. ramosa L. Unlike known autotrophic plants, the parasite metabolized L-tryptophan directly to indole-3-carboxaldehyde, which was further converted to indole-3-methanol and indole-3-carboxylic acid. Independently, these metabolites were also formed from D-tryptophan, tryptamine, indole-3-lactic acid, and indole-3-acetic acid. As in autotrophic plants, tryptophan and tryptamine were also converted, via indole-3-acetaldehyde, to indole-3-acetic acid, indole-3-ethanol, and its glucoside. free from adhering soil and stored overnight. The plant material was cut into sections about 1 cm in length. Boiled plant material was prepared in flasks immersed in a boiling water bath for 30 min.Incubation Procedure. Substrate solutions (1 ml/g of plant material) were prepared in 0.067 M KH2PO4 (pH 4.5) at approximate concentrations of 1 mg/ml for D-and L-tryptophan, tryptamine hydrochloride, indole-3-lactic acid, and tryptophol, and 0.1 mg/ml for IAA, indole-3-acetaldehyde, indole-3-methanol, indole-3-carboxaldehyde, and indole-3-carboxylic acid. Inhibitors were added to the substrate solutions at 1 to 2 mg/ml for cycloserine and semicarbazide hydrochloride and 0.1 mg/ml for KCN. These solutions were vacuum-infiltrated (at 20 mm Hg) into the plant sections. The sections took up about one-quarter of the solutions, a great deal of which was retained in dead space, such as that in between bracts and in flower buds. Intemal substrate levels per g of metabolically active plant tissue are, thus, smaller than are those per ml of the external solutions by at least one order of magnitude. The plant material and the remaining substrate solutions were incubated separately at 22°C for 5 h, the latter with aeration.Prepurification of Plant Extracts. After incubation, the plant material was homogenized in a 2-fold (w/v) amount of methanol.The homogenate was filtered, and the residue was reextracted. The combined filtrates were stored at -10°C until used. They were then concentrated in vacuo to a few ml; methanol (50 ml) was added, and the mixture was left at -10°C overnight. The precipitate was discarded, and the filtrate was concentrated in vacuo, adjusted to 10 ml with methanol, and extracted, once with 30 ml and a second time with 15 ml of benzene. The combined extracts were evaporated and the residue extracted with 5 x

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Section: Methodsmentioning

confidence: 99%

Metabolism of Tryptophan, Indole-3-acetic Acid, and Related Compounds in Parasitic Plants from the Genus Orobanche

Magnus¹,

Šimaga²,

Iskrić³

et al. 1982

Plant Physiol.

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“…These observations are in agreement with the findings of Thesing (25) who noted a breakdown of IM under acidic conditions, but described IM as stable under neutral and basic conditions. The degradation of IM under acidic conditions has also been described by other investigators (3,12). The proposed products obtained from IM degradation include BIM (25), 3-methyleneindolenine (3), and an unknown polymer (12).…”

Section: Resultsmentioning

confidence: 72%

“…The degradation of IM under acidic conditions has also been described by other investigators (3,12). The proposed products obtained from IM degradation include BIM (25), 3-methyleneindolenine (3), and an unknown polymer (12). Magnus et al (13) Figure 2.…”

Section: Resultsmentioning

confidence: 72%

“…(14), and Phaseolus vulgaris (7) also yielded IM as one of the catabolic products. Indirect evidence for an IM pathway in plants comes from the identification of BIM, a proposed degradation product of IM, as a product of IAA catabolism in both a crude enzyme extract from Zea mays (3) and HRP (24). The possible production ofIM in a HRP/IAA system is also pointed out by Nakajima and Yamazaki (15).…”

mentioning

confidence: 95%

“…Both a decarboxylative and a nondecarboxylative pathway are suggested (e.g., 3,11,17). Reliable identifications of some of the possible catabolic products of IAA have been obtained with both in vitro and in vivo test systems.…”

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confidence: 99%

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Identification and Quantification of Indole-3-methanol in Etiolated Seedlings of Scots Pine (Pinus sylvestris L.)

Sundberg¹,

Sandberg²,

Jensen³

1985

Plant Physiol.

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Combined ps chromatography-mass spectrometry has been used to identify indole-3-methanol in a purified buffer extract Extraction and Purification. The cotyledons and hypocotyls of the etiolated seedlings were homogenized in 0.1 M phosphate buffer (pH 8.0) (0.5 g-ml1) containing 0.02% w/w of the antioxidant sodium diethyldithiocarbamate. The tissue homogenate was ultrasonicated for 15 min, filtered and saturated with (NH4)2SO4 to precipitate proteins. All these steps were performed at 4°C. The extract was then centrifugated for 40 min at 46,000g in a refrigerated centrifuge. For IM analyses, the supernatant was adjusted to pH 8.0 with 1 M NaOH, slurried with insoluble PVP (1 g.25 g-' tissue fresh weight) and passed through a column packed with 1 g of Amberlite (1). When IAA was analyzed, the pH was adjusted to 2.7 with 1 M HC1 before the XAD column. The XAD-7 column was eluted with 10 ml of ethyl acetate and hexane (70:30, v/v). The aqueous phase of the eluate was discarded and 0.02% w/w of the antioxidant added to the organic phase prior to being reduced to dryness under a stream of N2 in preparation for HPLC.HPLC. Solvents were delivered via a LDC model 396 pump when isocratic elution was used, and via Waters model 45 and 510 pumps when gradient elution was utilized. Samples were introduced off-column via a Valco injector with a 100 1l loop. Column effluent was monitored with a Spectra-Physics SP-970 spectrofluorometric detector (excitation, 285 ± 5 nm; emission, 360 ± 10 nm) with a 5 ul flow cell. When radioactive components were analyzed, effluent leaving the fluorometer was directed to a Reeve Analytical radioactivity monitor operating in the heterogenous mode, with a 170 ;I flow cell packed with a ceriumactivated lithium glass scintilator. When necessary, radioactivity was quantified using an instagel scintillant and a LKB-Wallac Ultrabeta 1210 scintillation counter.Normal phase HPLC was performed using a 240 x 4.6 mm i.

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Wachstum

Schraudolf

1973

Fortschritte Der Botanik

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Mechanism of corn indole-3-acetic acid oxidase in vitro

Cited by 34 publications

References 37 publications

Metabolism of Tryptophan, Indole-3-acetic Acid, and Related Compounds in Parasitic Plants from the Genus Orobanche

Metabolism of Tryptophan, Indole-3-acetic Acid, and Related Compounds in Parasitic Plants from the Genus Orobanche

Identification and Quantification of Indole-3-methanol in Etiolated Seedlings of Scots Pine (Pinus sylvestris L.)

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