Methionine metabolism in apple tissue in relation to ethylene biosynthesis

Baur, A. H.; Yang, Shang Fa

doi:10.1016/s0031-9422(00)86375-x

Cited by 65 publications

(38 citation statements)

References 18 publications

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“…In the mungbean system, added methionine was ineffective in alleviating the inhibition by canaline. This may be interpreted on the basis that mungbean hypocotyls contain a relatively large pool of free methionine (17), as compared to apple tissue (2), and that binding of canaline to coenzyme was very strong in the mungbean system. Alternatively, since a structural similarity exists between canaline and methionine (the terminal methylthio group of methionine is replaced by an aminooxy group), canaline may exert its inhibitory effect not by interacting with pyridoxal phosphate but by a competitive type inhibition.…”

Section: Discussionmentioning

confidence: 99%

Inhibition of in Vivo Conversion of Methionine to Ethylene by l-Canaline and 2,4-Dinitrophenol

Murr

Yang²

1975

Plant Physiol.

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L-Canaline, a potent inhibitor of pyridoxal phosphate-mediated reactions, markedly inhibited the conversion of methionine to ethylene and carbon dioxide by apple tissue. A 50% inhibition of methionine conversion into ethylene was obtained with 50 jtM canaline and almost complete inhibition with 300 AM canaline. When 2, 4-dinitrophenol, an oxidative phosphorylation uncoupler, was fed to apple tissue, it inhibited the conversion of radioactive methionine to ethylene by 50% at a concentration of 60 AM and by 90% at a concentration of 100ItM. Production of labeled carbon dioxide from acetate-l-'4C was increased by 2,4-dinitrophenol, indicating that the inhibition of ethylene production was due to uncoupling of phosphorylation. Auxin-induced ethylene production by mungbean (Phaseolus mungo L.) hypocotyl sections was similarly inhibited by these inhibitors.These results support the proposal that pyridoxal phosphate is involved in the formation of ethylene from methionine, substantiate the requirement for ATP in ethylene production, and suggest that this ATP requirement occurs in the step(s) between methionine and ethylene. The biosynthetic mechanism probably involves activation of methionine by ATP followed by a pyridoxal phosphate-mediated y-elimination.Evidence from tracer studies has established methionine as the in vivo precursor of ethylene in fruit and vegetative tissues (1. 3,6,12,17,21). Conversion of methionine to ethylene in apple tissues represents the major pathway of methionine metabolism (6) and has an absolute requirement for 02 (3). A requirement for oxidative phosphorylation in the endogenous synthesis of ethylene has been demonstrated by inhibitor studies using respiratory uncouplers (8,11,20). Although DNP,2 a respiratory uncoupler, has been reported to inhibit the in vivo conversion of methionine to ethylene (4), the dependence of methionine conversion to ethylene on DNP concentration was not investigated.Recently it was found that rhizobitoxine, a phytotoxin produced by Rhizobium japonicum, markedly inhibited ethylene evolution by untreated and IAA-or kinetin-treated sorghum seedlings as well as inhibiting the formation of ethylene from 1 This work was supported by National Science Foundation Grant GB-33907X. (14) and spinach (10), Owens et al. (15) suggested that pyridoxal phosphate acted as a cofactor in the conversion of methionine to ethylene. Yang and Baur (21) proposed a concerted y-elimination reaction mechanism involving pyridoxal phosphate and 02 to account for the biological production of ethylene from methionine.We have found that L-canaline (2-amino-4-aminooxybutyric acid), a structural analog of L-ornithine, effectively inhibits the conversion of methionine to ethylene in apple tissue. L-Canaline has been shown to complex strongly with pyridoxal phosphate and inhibit activity of pyridoxal-dependent enzymes (16). This paper describes the effect of DNP and L-canaline on the conversion of L-methionine to ethylene in apple tissue and on the ethylene evolution by auxin-treated mu...

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Section: Discussionmentioning

confidence: 99%

Inhibition of in Vivo Conversion of Methionine to Ethylene by l-Canaline and 2,4-Dinitrophenol

Murr

Yang²

1975

Plant Physiol.

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“…Consistent with a low-sulfur state, we observed upregulation in fruits of several genes related to sulfur sensing and scavenging, including SDI1, a sulfur-sensing gene, and upregulation of BGL, which encodes a β-glucosidase that cleaves sulfur from glucosinolate 44 . An additional pathway for salvaging sulfur from MTA is the Yang cycle, which allows sulfur moieties from MTA to be recycled back to methionine 45,46 . In summary, our results suggest that the complex aroma of durian is possibly linked to durian fruit ripening, as both ethylene and VSC production are connected to the same regulatory processes and metabolites.…”

Section: A R T I C L E Smentioning

confidence: 99%

“…Using the Maker pipeline 13 , we incorporated 151,593 protein sequences from four plant species and 43,129 transcripts assembled from D. zibethinus Musang King RNA-seq data. 45,335 gene models were identified, with an average coding-sequence length of 1.7 kb and an average of 5.8 exons per gene. The vast majority of gene predictions (42,747) were supported by homology to known proteins, existence of known functional domains, or the presence of expressed transcripts (Supplementary Fig.…”

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confidence: 99%

The draft genome of tropical fruit durian (Durio zibethinus)

et al. 2017

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“…The existence of a recycling pathway for Met was first postulated by Baur and Yang (1972), and the first enzymatic activities of plant Met Cycle enzymes, 59-methylthioribose kinase (MTK) and 59-methylthioadenosine nucleosidase (MTN), were found 5 years later in extracts from lupin seeds (Guranowski, 1983). The first genes encoding plant Met Cycle enzymes (MTK from Arabidopsis [Arabidopsis thaliana] and MTK1 and MTK2 from rice [Oryza sativa]) were cloned 20 years later (Sauter et al, 2004).…”

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confidence: 99%

“…During these phases, elevated Met Cycle activity helps to replenish the Met pool (Baur and Yang, 1972;Bürstenbinder et al, 2007;Rzewuski et al, 2007). Utilizing a mtk mutant, the ethylene overproducing mutant eto3, and the mtk/eto3 double mutant, Bürstenbinder et al (2007) could show that the Met Cycle is important during periods of high ethylene synthesis in seedlings.…”

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confidence: 99%

Phloem-Specific Methionine Recycling Fuels Polyamine Biosynthesis in a Sulfur-Dependent Manner and Promotes Flower and Seed Development

et al. 2015

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The Yang or Met Cycle is a series of reactions catalyzing the recycling of the sulfur (S) compound 59-methylthioadenosine (MTA) to Met. MTA is produced as a by-product in ethylene, nicotianamine, and polyamine biosynthesis. Whether the Met Cycle preferentially fuels one of these pathways in a S-dependent manner remained unclear so far. We analyzed Arabidopsis (Arabidopsis thaliana) mutants with defects in the Met Cycle enzymes 5-METHYLTHIORIBOSE-1-PHOSPHATE-ISOMERASE1 (MTI1) and DEHYDRATASE-ENOLASE-PHOSPHATASE-COMPLEX1 (DEP1) under different S conditions and assayed the contribution of the Met Cycle to the regeneration of S for these pathways. Neither mti1 nor dep1 mutants could recycle MTA but showed S-dependent reproductive failure, which was accompanied by reduced levels of the polyamines putrescine, spermidine, and spermine in mutant inflorescences. Complementation experiments with external application of these three polyamines showed that only the triamine spermine could specifically rescue the S-dependent reproductive defects of the mutant plants. Furthermore, expressing gene-reporter fusions in Arabidopsis showed that MTI1 and DEP1 were mainly expressed in the vasculature of all plant parts. Phloem-specific reconstitution of Met Cycle activity in mti1 and dep1 mutant plants was sufficient to rescue their S-dependent mutant phenotypes. We conclude from these analyses that phloem-specific S recycling during periods of S starvation is essential for the biosynthesis of polyamines required for flowering and seed development.

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Methionine metabolism in apple tissue in relation to ethylene biosynthesis

Cited by 65 publications

References 18 publications

Inhibition of in Vivo Conversion of Methionine to Ethylene by l-Canaline and 2,4-Dinitrophenol

Inhibition of in Vivo Conversion of Methionine to Ethylene by l-Canaline and 2,4-Dinitrophenol

The draft genome of tropical fruit durian (Durio zibethinus)

Phloem-Specific Methionine Recycling Fuels Polyamine Biosynthesis in a Sulfur-Dependent Manner and Promotes Flower and Seed Development

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