The enzymic breakdown of lipids to volatile and non‐volatile carbonyl fragments in disrupted tomato fruits

Galliard, T.; Matthew, Jennifer A.; Wright, A.; Fishwick, Michael J.

doi:10.1002/jsfa.2740280915

Cited by 95 publications

(43 citation statements)

References 26 publications

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“…The odd-and even-numbered carbon chains might be the product of a-oxidation and /S-oxidation of fatty acids (Gerhardt, 1993), or of modification of branched-chain amino acids (Kroumova, Zhiyi & Wagner, 1994). The synthesis of aldehydes and alcohols has not been studied extensively (Galliard et al,, 1977), but they might arise from unsaturated hydroperoxides of various fatty acids (Eorss, 1972;Erankel, 1982). For example, n-hexanal is formed from linoleic acid (Galliard et al, 1977).…”

Section: Discussionmentioning

confidence: 99%

The Sauromatum guttatum appendix as an osmophore: excretory pathways, composition of volatiles and attractiveness to insects

et al. 1996

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summary This report combines chemical, electron microscopic and ecological studies on the volatiles liberated by the Sauromatum guttatum appendix on D‐Day, the day of inflorescence‐opening and heat‐production. More than 100 compounds from at least nine different chemical classes (monoterpenes, sesquiterpenes, fatty acids, ketones, alcohols, aldehydes, indole, and phenolic and sulphur compounds) are liberated during the thermogenic activity. The volatiles were identified using gas chromatography‐mass spectrometry. Electron microscopy provides additional evidence that the endoplasmic reticulum (ER) interacts with the plasma membrane, creating novel routes of excretion of the volatiles to the exterior of the cell. It seems that the fusion event creates channels from the interior to the exterior of the cell. Furthermore, a multitubular body, conceivably originating in the ER, seems to fuse with the plasma membrane and to appear only on D‐day. This multitubular body is closely associated with lipid bodies during heat‐production and might be involved in the oxidation of lipids to volatile products. The foul odour produced by the appendix attracts at least 30 species of insects.

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Section: Discussionmentioning

confidence: 99%

The Sauromatum guttatum appendix as an osmophore: excretory pathways, composition of volatiles and attractiveness to insects

et al. 1996

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“…The enzyme speci®cally cleaves 13-hydroperoxides (Jadhav, Singh & Salunkhe, 1972;Galliard, Matthew, Wright & Fishwick, 1977), although in crude enzyme preparations some formation of 2E-nonenal from 9-HPOD was observed (Hatanaka, Kajiwara, Matsui & Kitamura, 1992). Schreier and Lorenz (1982) achieved a 5-fold puri®cation of the enzyme but further enrichment was dicult because the activity was rapidly lost.…”

Section: Introductionmentioning

confidence: 99%

Purification, stabilization and characterization of tomato fatty acid hydroperoxide lyase

et al. 2000

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Fatty acid hydroperoxide lyase (HPO-lyase) was puri®ed 300-fold from tomatoes. The enzymatic activity appeared to be very unstable, but addition of Triton X 100 and b-mercaptoethanol to the buer yielded an active enzyme that could be stored for several months at À808C. The enzyme was inhibited by desferoxamine mesylate (desferal), 2-methyl-1,2-di-3-pyridyl-1-propanone (metyrapone), nordihydroguaiaretic acid (NDGA), n-propyl gallate and butylated hydroxyanisole, suggesting the involvement of free radicals in the reaction mechanism and the existence of a prosthetic group in the active center. However, no heme group could be demonstrated with the methods commonly used to identify heme groups in proteins. Only 13-hydroperoxides from linoleic acid (13-HPOD) and a-linolenic acid (a-13-HPOT) were cleaved by the tomato enzyme, with a clear preference for the latter substrate. The pH-optimum was 6.5, and for concentrations lower than 300 mM a typical Michaelis±Menten curve was found with a K m of 77 mM. At higher a-13-HPOT concentrations inhibition of the enzyme was observed, which could (at least in part) be attributed to 2E-hexenal. A curve of the substrate conversion as a function of the enzyme concentration revealed that 1 nkat of enzyme activity converts 0.7 mmol a-13-HPOT before inactivation. Headspace analysis showed that tomato HPO-lyase formed hexanal from 13-HPOD and 3Z-hexenal from a-13-HPOT. A trace of the latter compound was isomerized to 2E-hexenal. In addition to the aldehydes, 12-oxo-9Z-dodecenoic acid was found by GC/MS analysis. To a small extent, isomerization to 12-oxo-10E-dodecenoic acid occurred. #

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“…Three of these plants, cucumber, muskmelon, and watermelon, have been shown previously to possess the hydroperoxide lyase enzyme (8). Examples of hydroperoxide-cleaving activity have also been shown in cucumber (3) and tomato fruit (2), and in leaves of Phaseolus vulgaris (6) and Thea sinensis (4 …”

Section: Resultsmentioning

confidence: 98%

Distribution of a Fatty Acid Cyclase Enzyme System in Plants

Vick¹,

Zimmermann²

1979

Plant Physiol.

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Extracts from tissues of 24 plant species were tested for the enzyme that catalyzes the conversion of 13-L-hydroperoxy-cis-9,15-tws-11-ctadecatrienoic acid to the cyclic fatty acid 12-oxo-cis-10,15-phytodikeoic acid.The enzyme was detected in 15 of the 24 tissues examined, and was demonstrated in seelings, leaves, and fruits.Recently, Zimmerman and Feng (10) reported the synthesis of a cyclic, prostaglandin-like fatty acid from (9,12,15)-linolenic acid, catalyzed by an enzyme in flaxseed. The compound, 8-[2-(cispent-2'-enyl)-3-oxo-cis-cyclopent-4-enyl]octanoic acid, is analogous to the prostaglandins of the A-type, and the common name 12-oxo-cis-10,15-phytodienoic acid was proposed to avoid the cumbersome systematic nomenclature. The structure of the cyclic fatty acid is shown in Figure 1. In another report we showed (9) that other polyunsaturated fatty acids in addition to (9,12,15)-linolenic acid could be utilized as substrates in the synthesis of cyclic fatty acids. Fatty acids with 18, 20, or 22 carbons could be enzymically converted to cyclic compounds provided they were unsaturated at the n-3,6,9 positions. We further showed that an n-6 hydroperoxide of the fatty acid was an intermediate in the biosynthetic pathway (Fig. 1). The hydroperoxide is also an intermediate in the synthesis of another fatty acid, 12-oxo-13-hydroxy-cis-9,15-octadecadienoic acid, catalyzed by a hydroperoxide isomerase enzyme (1 1). Here, we report the presence of the enzyme that catalyzes the synthesis of a cyclic fatty acid from the 13-hydroperoxide of (9,12,15) Prepartion of Enzyme Solutions. For seedlings, the intact plants without seed coats were used. Potato tubers and the fleshy portion of the fruits of apple and eggplant (seeds removed) were diced prior to enzyme extraction. Each plant tissue was frozen with liquid N2 in a mortar and ground with a pestle. When the tissue thawed, the extraction medium containing 1.5% Triton X-100 in 0.05 M K-phosphate (pH 7.0) was added. One ml of buffer was added for each gram of plant tissue. The tissue was ground in the extraction medium, filtered through four layers of cheesecloth, centrifuged at 12,000g for 10 min, and the supernatant used as the enzyme source.Enzyme Assay. The substrate for the fatty acid cyclase enzyme. 13-L-hydroperoxy-cis-9,15-trans-11-octadecatrienoic acid, was prepared in situ for each assay by reacting 0.74 ml of an 8 mm (9,12,15)-linolenic acid-Tween 20 substrate solution (7) with 2 mg of soybean lipoxygenase in 23.5 ml of 0.8 mm borate buffer (pH 9.0). After 45 min the mixture was adjusted to pH 7.2 by the addition of 5.9 ml of 0.2 M K-phosphate (pH 7.0) containing 600 Lmol of 9-oxo-hexadecanoic acid as an internal standard. The enzyme reaction was initiated by the addition of 0.8 to 4.0 ml of the plant extract and stopped after intervals ranging from 0.5 to 15 min by addition of 7.5-ml portions of the reaction mixture to 10 ml ofchloroform-methanol solvent (2:1, v/v). Then the pH was adjusted to 3.9 with 1 M citric acid and the products partitioned into...

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The enzymic breakdown of lipids to volatile and non‐volatile carbonyl fragments in disrupted tomato fruits

Cited by 95 publications

References 26 publications

The Sauromatum guttatum appendix as an osmophore: excretory pathways, composition of volatiles and attractiveness to insects

The Sauromatum guttatum appendix as an osmophore: excretory pathways, composition of volatiles and attractiveness to insects

Purification, stabilization and characterization of tomato fatty acid hydroperoxide lyase

Distribution of a Fatty Acid Cyclase Enzyme System in Plants

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