Formation of Tryptophol Galactoside and an Unknown Tryptophol Ester in <i>Euglena gracilis</i>

Laćan, Goran; Magnus, Volker; Jeričević, Biserka; Kunst, Ljerka; Iskrić, Sonja

doi:10.1104/pp.76.4.889

Cited by 11 publications

(6 citation statements)

References 15 publications

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“…A small amount of Trp is converted into indole by the action of bacterial tryptophanase enzyme in the gut. A number of organisms convert tryptophol into other derivatives, such as indole acetaldehyde, and glucoside, galactoside and mannoside conjugates of unknown function [ 56 , 57 , 58 ]. Finally, tryptophol is a starting material for many natural and synthetic bioactive compounds that have been masterly described in a recent treatise [ 59 ].…”

Section: Metabolism Of Trpmentioning

confidence: 99%

The Uniqueness of Tryptophan in Biology: Properties, Metabolism, Interactions and Localization in Proteins

Barik

2020

IJMS

125

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Tryptophan (Trp) holds a unique place in biology for a multitude of reasons. It is the largest of all twenty amino acids in the translational toolbox. Its side chain is indole, which is aromatic with a binuclear ring structure, whereas those of Phe, Tyr, and His are single-ring aromatics. In part due to these elaborate structural features, the biosynthetic pathway of Trp is the most complex and the most energy-consuming among all amino acids. Essential in the animal diet, Trp is also the least abundant amino acid in the cell, and one of the rarest in the proteome. In most eukaryotes, Trp is the only amino acid besides Met, which is coded for by a single codon, namely UGG. Due to the large and hydrophobic π-electron surface area, its aromatic side chain interacts with multiple other side chains in the protein, befitting its strategic locations in the protein structure. Finally, several Trp derivatives, namely tryptophylquinone, oxitriptan, serotonin, melatonin, and tryptophol, have specialized functions. Overall, Trp is a scarce and precious amino acid in the cell, such that nature uses it parsimoniously, for multiple but selective functions. Here, the various aspects of the uniqueness of Trp are presented in molecular terms.

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Section: Metabolism Of Trpmentioning

confidence: 99%

The Uniqueness of Tryptophan in Biology: Properties, Metabolism, Interactions and Localization in Proteins

Barik

2020

IJMS

125

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“…The enzyme would also hydrolyze tryptophol l-D-xylopyranoside, f3-D-fucopyranoside, and a-L-arabinopyranoside (28). However, these glycosides are chromatographically distinct from tryptophol glucoside and galactoside (10).…”

mentioning

confidence: 99%

“…About 40 ,g/g fresh weight was obtained from Lemna,10 ,gg/g from the alga Chara and the mosses Leucobryum and Fissidens, and 0.2 to 0.5 ug/g from the mushroom Agaricus, the clubmoss Lycopodium, and the seed plants Calluna and Lythrum. These values are not corrected for recoveries during isolation and purification which are, however, to our experience, fairly reproducible with the quantities of IAA encountered.…”

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confidence: 99%

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Metabolism of Tryptophol in Higher and Lower Plants

Laćan¹,

Magnus²,

Šimaga³

et al. 1985

Plant Physiol.

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Bacteria, thallophytes, and seed plants (107 species), supplied with exogenous indole-3-ethanol (tryptophol), formed one or more of the following metabolites: O-acetyl tryptophoL an unknown tryptophol ester (or a set of structurally closely related esters), tryptophol glucoside, tryptophol plactoside, indole-3-acetic acid (IAA), and indole-3-carboxylic acid. The unknown ester was formed by all species exAmined; 0-acetyl tryptophol appeared sporadically in representatives of most major taxonomic groups. Tryptophol galactoside was found in the algae Chlorella, Euglena, and Ochromoaas. The glucoside was formed by many eucaryotic plants, but not by bacteria; it was a significant tryptophol metabolite in vascular plants. IAA, if detectable at all, was usually a minor metabolite, as should be expected, if tryptophol oxidase responds to feedback inhibition by IAA. Indole-3-carboxylic acid, formed by a few fungi and mosses, was the only tryptophol metabolite detected which is likely to be formed via IAA.Indole-3-ethanol (tryptophol2) has been established as an endogenous plant constituent (6,19,23). It is also formed in vitro by preparations from bacteria, thallophytes, and seed plants from compounds supposed to participate in the biogenesis of IAA (e.g. 18,23). In fact, tryptophol appears to be in an oxidase-reductasemediated equilibrium with the IAA precursor, indole-3-acetaldehyde (5, 16). The oxidase has been isolated and found to be feedback inhibited by IAA (16). This points to the involvement of tryptophol in a mechanism stabilizing auxin levels in plants. Its in vivo significance has, however, remained unclear, because IAA concentrations necessary to inhibit the isolated tryptophol oxidase are larger than bulk concentrations of the hormone in plant tissues (16).Local IAA concentrations at points ofregulation may be higher than bulk concentrations. Also, removal of tryptophol oxidase from its natural subcellular environment may render the enzyme less sensitive to feedback inhibitors. For these reasons, we were looking for indications of regulated IAA formation from tryptophol in systems containing nondisrupted cell structures. Suspensions of unicellular plants and sections of multicellular plants were supplied with a large excess of tryptophol. In the absence of regulatory mechanisms, this might reasonably be expected to lead to drastically enhanced IAA levels. However, the majority of plants examined did not accumulate substantial amounts of 2 Abbreviations: tryptophol, indole-3-ethanol or 3-(2-hydroxyethyl)indole; Ve, elution volume.The most abundant tryptophol metabolites in bacteria, thallophytes, and seed plants were conjugates: esters and glycosides.MATERIALS AND METHODS Instrumentation. 'H NMR spectra were recorded at 100 MHz on a JEOL FX-100 Fourier-transform spectrometer. Chemical shifts (a) were recorded relative to tetramethylsilane. GC-MS was on a Hewlett-Packard 5985a instrument, using helium at 30 ml/ min as the carrier gas and electron impact ionization at 70 ev. Columns and temperature pr...

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“…Some preliminary studies indicate that a membranebound enzyme system in P. blakesleeanus is capable of oxidizing IEt directly to IAA (P. Schramm, unpublished results). A role for IAA conjugates (Hall and Bandurski 1986) and IEt conjugates (Lacan et al 1984, Fetin et al 1977 in the regulation of IAA content in P. blakesleeanus could not be established since these compounds have not yet been detected in the fungus. HPLC equipment.…”

Section: Iaald Reductase Of Phycomyces Blakesleeanus Has Sotne Featurmentioning

confidence: 98%

Indole‐3‐acetaldehyde reductase in Phycomyces blakesleeanus. Characterization of the enzyme

Ludwig‐Müller

Schramm

Hilgenberg

1990

Physiologia Plantarum

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W. 1990. Indole-3-acctaldehyde reductase in Phyeomyces btakesleeantis. Characterization of the enzyme. -Physiol Plant. 80: 472-478. Indole-3-acetaldehyde reductase (IAAld reductase EC 1.2.3.1) from Phycomyces btakesleeanus Bgff., a 38 kDa polypeptide as determined by gel filtration, is probably localized in the cytoplasm. The formation of indoie-3-ethanol (lEt) is dependent on the presence of NAD(P)H. The enzymatic reduction of IAAld shows a pH optimum between 6 and 8 and a temperature optimum at 30°C. Enzyme activity follows Michaelis Menten kinetic (K_ = 200 fiM for IAAld; K^ = 24 \>.M for NADPH), The isoelectric point of the IAAld reductase is at pH 5.4. Phenylacetaldehyde and benzaldehyde are competitive substrates. Hydroxymethylindole promotes the reductive IEt formation, whereas NADP* is a non-competitive inhibitor. Changes in IAAld reductase activity correlate with certain developmental stages of the fungus.

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Formation of Tryptophol Galactoside and an Unknown Tryptophol Ester in Euglena gracilis

Cited by 11 publications

References 15 publications

The Uniqueness of Tryptophan in Biology: Properties, Metabolism, Interactions and Localization in Proteins

The Uniqueness of Tryptophan in Biology: Properties, Metabolism, Interactions and Localization in Proteins

Metabolism of Tryptophol in Higher and Lower Plants

Indole‐3‐acetaldehyde reductase in Phycomyces blakesleeanus. Characterization of the enzyme

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