Biosynthesis of ethylene. Formation of ethylene from methional by a cell-free enzyme system from cauliflower florets

Mapson, L. W.; Wardale, D. A.

doi:10.1042/bj1020574

Cited by 41 publications

(17 citation statements)

References 8 publications

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“…The C, of methionine was released as CO,, C,-C4 were released as ethylene, and the rest of the carbon atoms were retained in the tissues and widely inetabolized. Mapson and Wardale (1967) and Ku et 01. (1967) showed that extracts of cauliflower florets and pea seedlings formed ethylene from methional.…”

Section: Discussionmentioning

confidence: 93%

Gaseous and volatile exudates from germinating seeds and seedlings

Vančura¹,

Stotzky²

1976

Can. J. Bot.

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V A N~U R A . V . . and G. STOTZKY. 1976. Gaseous and volatile exudatesfromgerminatingseeds and seedlings. Can. J. Bot. 54: 518-532. The quantitiesof gaseous and volatile metabolites liberated by germinating seeds and seedlings appeared to be related, ingeneral, to the amount of storage substances present in the seeds. Both qual~tative and quantitative differences were found between various plant species and varieties of both angiosperms and gymnosperms. The release of volatile compounds preceded the appearance of the first root and, with most seeds, was greatest in the first 24 to 48 h. Organic volatiles could be detected, by gas chromatography. in as little as 5% of the atmosphere from one germinating seed. All seeds that were studied liberated ethanol, and most seeds evolved methanol. formaldehyde, acetaldehyde, formic acid, ethylene. and propylene. Propionaldehyde and (or) acetone was also evolved by cotton, pea. and yellow pine. The possible source of these volatile metabolites and their ecological implications are discussed. V A N~U R A .V . . et G. STOTZKY. 1976. G a s e o~~s and volatile exudates from germinating seeds and seedlings. Can. J . Bot. 54: 518-532. La quantite de metabolites gazeux et volatiles IibCrCs par les graines en germination et les plant~lles semble reliee. en general, a la quantite de substances d'entreposage presentes dans les gl-aines. Des differences q~lalitatives et quantitatives ont ete trouvies entre diverses especes et varietes de plantes, aussi bien chez desangiospermes que chezdesgymnospermes. La liberation de composes volatiles precede I'apparition de la premiere racine et. chez la plupart des gl-aines, est plus intense au cours des premieres 24 a 48 h. A I'aide de la chromatographie en phase gazeuse. des composes volatiles organiques ont pu ktre deceles dans aussi peu que 5% d e

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Section: Discussionmentioning

confidence: 93%

Gaseous and volatile exudates from germinating seeds and seedlings

Vančura¹,

Stotzky²

1976

Can. J. Bot.

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“…Extracts of pea seedlings (20) and cauliflower florets (23) contain an enzyme capable of converting methional to ethylene, and horseradish peroxidase will catalyze the same T IME (hr) TIME ( reaction in the presence of suitable cofactors (30). Yang (30) speculated that the pea system may be a peroxidase and later Mapson and Wardale (24) further characterized the cauliflower enzyme system and concluded that the enzyme may indeed be a peroxidase.…”

Section: Discussionmentioning

confidence: 99%

Mechanism of Auxin-induced Ethylene Production

1971

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Indoleacetic acid-induced ethylene production and growth in excised segments of etiolated pea shoots (Pisum sativum L. var. Alaska) parallels the free indoleacetic acid level in the tissue which in turn depends upon the rate of indoleacetic acid conjugation and decarboxylation. Both ethylene synthesis and growth require the presence of more than a threshold level of free endogenous indoleacetic acid, but in etiolated tissue the rate of ethylene production saturates at a high concentration and the rate of growth at a lower concentration of indoleacetic acid. Auxin stimulation of ethylene synthesis is not mediated by induction of peroxidase; to the contrary, the products of the auxin action which induce growth and ethylene synthesis are highly labile.It has been suggested that auxin may stimulate ethylene production by inducing the enzymes involved in the formation of the gas (1). This theory is based primarily upon the finding that inhibitors of protein and RNA synthesis prevent auxininduced ethylene production, and also on the observation that stimulation of ethylene production by auxin has a substantial lag period (1,5,7,18,19). Extracts of pea seedlings contain an enzyme that converts methional to ethylene in a cell-free system (20). The enzyme has been identified as a peroxidase (30), a protein which also catalyzes a number of other reactions including oxidation of IAA (13,14,26). The present study presents evidence which shows the peroxidase content not to play a role in the regulation of ethylene biosynthesis in pea seedlings. Growth, ethylene production, the endogenous IAA content, exogenous IAA level, and rate of metabolism of growth hormone were continuously determined and compared in an attempt to determine the mechanism by which auxin induces ethylene production. (29) which is approximately 100% efficient. The radioactivity remaining in the tissue after alcohol extraction was determined after squashing the sections and drying them on a planchet, under which condition self-absorption was negligible. Enzyme Assay for Ethylene Synthesis. Sections of subapical internodes or plumular hooks were homogenized in 50 mm potassium phosphate buffer at pH 7.8 (10 sections/ml), strained through cheesecloth, and centrifuged at lOOOg for 15 min. The preparation could be further purified by dialysis and ammonium sulfate precipitation as described by Ku et al. for the pea enzyme (20), but a variable loss in activity occurred at each step, making the crude extract preferable for quantitative studies. The resulting supernatant (enzyme preparation) was assayed in 5 ml of reaction mixture described by Yang (30), consisting of 10 mM potassium phosphate buffer (pH 7.8), 0.6 mm methional, 3 em manganese sulfate, 80 mm resorcinol, 2 ytM ethylenediaminetetraacetic acid, 80 fM sodium hydrogen sulfite, with 1 ml of enzyme extract. The mixture was incubated at 25 C in a 25-ml Erlenmeyer flask sealed with a vaccine cap, and typically 1-ml samples of air were withdrawn from the flask at 30-min intervals, and ethylene was ...

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“…The fact that the plant enzymes were involved pointed to the possibility that the increased rate of synthesis was simply due to a stimulation of the normal synthetic system. Recent work has shown that ethylene is formed from methionine in plants, and the biosynthetic route was described by Mapson & Wardale (1967. In floret tissue, the synthesis of ethylene depends on (1) a transaminase converting methionine into 4-methylmercapto-2-oxobutyric acid (oxo acid), (2) a glucose oxidase generating hydrogen peroxide from the oxidation of D-glucose, and (3) the presence of a peroxidase utilizing the peroxide so formed to catalyse the production of ethylene from the C-3 and C-4 carbon atoms of the oxo acid.…”

Section: Addition To Flaskmentioning

confidence: 99%

Stimulation by Erwinia carotovora of the synthesis of ethylene in cauliflower tissue

Lund

Mapson

1970

Biochemical Journal

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The synthesis of ethylene by cauliflower floret tissue was increased when the tissue was inoculated with the soft-rot bacterium Erwinia carotovora. This effect was clearly associated with the production of pectic enzymes by the micro-organism. These enzymes, acting together with the plant enzymes, stimulated the production of ethylene from methionine. The increased synthetic activity was due to the release and increased activity of a glucose oxidase enzyme apparently attached to plant cell-wall material and liberated by the action of pectic enzymes of the bacterium.

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Biosynthesis of ethylene. Formation of ethylene from methional by a cell-free enzyme system from cauliflower florets

Cited by 41 publications

References 8 publications

Gaseous and volatile exudates from germinating seeds and seedlings

Gaseous and volatile exudates from germinating seeds and seedlings

Mechanism of Auxin-induced Ethylene Production

Stimulation by Erwinia carotovora of the synthesis of ethylene in cauliflower tissue

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