Recent investigations into the lipoxygenase pathway of plants

Gardner, Harold W.

doi:10.1016/0005-2760(91)90063-n

Cited by 517 publications

(323 citation statements)

References 150 publications

Supporting

Mentioning

300

Contrasting

Unclassified

Order By: Relevance

“…There have been no previous reports of plant GSTs exhibiting activity with 4HNE. In plants alkenals such as trans-2-hexenal are derived from 13-hydroperoxylinolenic acid after cleavage with hydroperoxide lyase (Gardner, 1991). An Arabidopsis GST active with 13-hydroperoxylinolenic acid exhibited no activity with trans-2-hexenal (Bartling et al, 1993).…”

Section: Discussionmentioning

confidence: 99%

Isolation and Characterization of GlutathioneS-Transferase Isozymes from Sorghum1

1998

View full text Add to dashboard Cite

Two glutathione S-transferase (GST) isozymes, A1/A1 and B1/B2, were purified from etiolated, O-1,3-dioxolan-2-yl-methyl-2,2,2,-trifluoro-4 -chloroacetophenone-oxime-treated sorghum (Sorghum bicolor L. Moench) shoots. GST A1/A1, a constitutively expressed homodimer, had a subunit molecular mass of 26 kD and an isoelectric point of 4.9. GST A1/A1 exhibited high activity with 1-chloro-2, 4,dinitrobenzene (CDNB) but low activity with the chloroacetanilide herbicide metolachlor. For GST A1/A1, the random, rapidequilibrium bireactant kinetic model provided a good description of the kinetic data for the substrates CDNB and glutathione (GSH). GST B1/B2 was a heterodimer with subunit molecular masses of 26 kD (designated the B1 subunit) and 28 kD (designated the B2 subunit) and a native isoelectric point of 4.8. GST B1/B2 exhibited low activity with CDNB and high activity with metolachlor as the substrate. The kinetics of GST B1/B2 activity with GSH and metolachlor fit a model describing a multisite enzyme having two binding sites with different affinities for these substrates. Both GST A1/A1 and GST B1/B2 exhibited GSH-conjugating activity with ethacrynic acid and GSH peroxidase activity with cumene hydroperoxide, 9-hydroperoxy-trans-10,cis-12-octadecadienoic acid and 13-hydroperoxy-cis-9,trans-11-octadecadienoic acid. Both GST A1/A1 and GST B1/B2 are glycoproteins, as indicated by their binding of concanavalin A. Polyclonal antibodies raised against GST A1/A1 exhibited cross-reactivity with the B1 subunit of GST B1/B2. Comparisons of the N-terminal amino acid sequences of the GST A1, B1, and B2 subunits with other type I -GSTs indicated a high degree of homology with the maize GST I subunit and a sugarcane GST.GSTs (EC 2.5.1.18) are dimeric enzymes found in mammals, insects, plants, and microbes that catalyze nucleophilic attack by the thiolate anion of GSH at electrophilic centers of hydrophobic molecules (Mannervik and Danielson, 1988). In addition to catalyzing GSH conjugation, GSTs also exhibit GSH peroxidase activity and ligandbinding functions (Mannervik and Danielson, 1988;Marrs, 1996). Mammalian GSTs compose a multigene family; in rat liver at least 13 different cytosolic GST subunits are found as either heterodimers or homodimers . Mammalian cytosolic GSTs have been divided into four classes (␣, , , and ) based on immunological, biochemical, and sequence similarities (Buetler and Eaton, 1992). It is well established that mammalian GSTs play an important role in the detoxification of electrophilic xenobiotics (Mannervik and Danielson, 1988). Although endogenous substrates for mammalian GSTs have not been clearly defined, there is evidence that ␣-GSTs protect against oxidative stress by detoxifying reactive products generated by lipid peroxidation (Ålin et al., 1985;Ketterer and Coles, 1991;Singhal et al., 1992).In general, plant GSTs have not been as well characterized as mammalian GSTs. Plant cytosolic GSTs belong to the archaic class of GSTs (Meyer et al., 1991;Marrs, 1996). This class, which is very heterog...

show abstract

Section: Discussionmentioning

confidence: 99%

Isolation and Characterization of GlutathioneS-Transferase Isozymes from Sorghum1

1998

View full text Add to dashboard Cite

show abstract

“…Cereal seeds have a high capacity of production of epoxy-hydroxy acids from linoleic and a-linolenic acids. It is well established that the initial step of these conversions consists of lipoxygenase-catalyzed oxygenation to afford hydroperoxides; however, the subsequent reaction by which hydroperoxides are converted into epoxy-hydroxy acids is incompletely understood (for review, see Gardner, 1988Gardner, , 1991. The present work was initiated to investigate whether peroxygenase is present in cereal seeds and to clarify Plant Physiol.…”

Section: Discussionmentioning

confidence: 99%

Peroxygenase-Catalyzed Fatty Acid Epoxidation in Cereal Seeds (Sequential Oxidation of Linoleic Acid into 9(S),12(S),13(S)-Trihydroxy-10(E)-Octadecenoic Acid)

Hámberg

Hamberg

1996

Plant Physiol.

View full text Add to dashboard Cite

Peroxygenase-catalyzed epoxidation of oleic acid in preparations of cereal seeds was investigated. The 105,OOOg particle fraction of oat (Avena safiva) seed homogenate showed high peroxygenase activity, i.e. 3034 2 288 and 2441 f 168 nmol (10 min)-' mg-' protein in two cultivars, whereas the corresponding fraction obtained from barley (Hordeum vulgare and Hordeum distichum), rye (Secale cereale), and wheat (Trificum aesfivum) showed only weak activity, i.e. dihydroxy-9(Z)-octadecenoic acid, and 12(R),13(S)-epoxy-9(S)-hy-droxy-1 O(€)-octadecenoic acid. lncubation of linoleic acid with the 105,OOOg particle fraction gave a similar, but not identical, pattern of metabolites. Conversion of linoleic acid into 9(S),12(S),13(S)-trihydroxy-1 O(€)-octadecenoic acid, a naturally occurring oxylipin with antifungal properties, took place by a pathway involving sequential catalysis by lipoxygenase, peroxygenase, and epoxide hydrolase.Formation of hydroxyoctadecadienoic acids and epoxyhydroxyoctadecenoic acids upon incubation of linoleic acid with wheat (Triticum aestivum) flour-water suspensions was described by Graveland (1970). In the same year, the presence of a "lipoperoxidase" activity in oat (Avena sntiva) seed was postulated to explain reduction of linoleic acid 9-and 13-hydroperoxides (9-HPOD and 13-HPOD) into the corresponding alcohols (9-and 13-HOD) (Heimann and Schreier, 1970). In a further study, oat seed was reported to '

show abstract

“…1.3.3(ii)). 55,81,89 These products bind covalently to amino acid side chains (-SH, -NH 2 ,TNH) and exert toxicity to insects including caterpillars and planthoppers. 55,[89][90][91][92] 4.08.1.2.2(vi) Lectins Lectins are proteins that bind to specific sugars and are found in a wide variety of plant species, but are abundant in legume seeds.…”

Section: 08122(iii) Proteinasementioning

confidence: 99%

“…55,81,89 These products bind covalently to amino acid side chains (-SH, -NH 2 ,TNH) and exert toxicity to insects including caterpillars and planthoppers. 55,[89][90][91][92] 4.08.1.2.2(vi) Lectins Lectins are proteins that bind to specific sugars and are found in a wide variety of plant species, but are abundant in legume seeds. [93][94][95][96] Typical lectins have multiple binding sites in each molecule, and thus they have cell agglutinating property, but some lectins have single binding site.…”

Section: 08122(iii) Proteinasementioning

confidence: 99%