Oxidative Decarboxylation of Branched-Chain 2-Oxo Fatty Acids by Higher Plant Peroxisomes

Gerbling, Heidrun; Gerhardt, Bernt

doi:10.1104/pp.88.1.13

Cited by 42 publications

(26 citation statements)

References 11 publications

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“…during sucrose starvation (16,20) when massive production of branched-chain amino acids is triggered during the course of macroautophagy. These hypotheses require further attention, and the physiological significance of the possible dual localization of leucine degradation in plant cells (peroxisomes [10,11], mitochondria [this work]) remains to be established. Finally, it is also possible that mitochondrial MCase can be involved in the mevalonate synthesis pathway (via 3-hydroxyl-3-methylglutaryl-CoA).…”

Section: Discussionmentioning

confidence: 99%

Characterization of Biotin and 3-Methylcrotonyl-Coenzyme A Carboxylase in Higher Plant Mitochondria

Baldet¹,

Alban²,

Axiotis³

et al. 1992

Plant Physiol.

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Mitochondria from green pea (Pisum sativum) leaves were purified free of peroxisomes and chlorophyll contamination and examined for their biotin content. The bulk of the bound biotin detected in plant mitochondria was shown to be associated with the matrix space to a concentration of about 13 micromolar, and no free biotin was detected. Western blot analysis of mitochondrial polypeptides using horseradish peroxidase-labeled streptavidin revealed a unique biotin-containing polypeptide with a molecular weight of 76,000. This polypeptide was implicated as being the biotinylated subunit of 3-methylcrotonyl-coenzyme A (CoA) carboxylase. Fractionation of pea leaf protoplasts demonstrated that this enzyme activity was located largely in mitochondria. The 3-methylcrotonyl-CoA carboxylase activity was latent when assayed in isotonic media. with MCase, which catalyzes the ATP-dependent carboxylation of the 3-methyl carbon of the branched acyl-CoA substrate to give 3-methylglutaconyl-CoA. MATERIALS AND METHODS ReagentsAll biochemicals were obtained from Sigma Chimie SARL, La Verpilliere, France. NaH'4CO3 (53.1 Ci/mol) was purchased from Amersham. Other chemicals were analytical grade. Plant MaterialsPea (Pisum sativum L., var Douce Provence) plants were grown from seeds in soil for 15 d under a 12-h photoperiod ofwhite light from fluorescent tubes (10-40 ,gE/m2/s) at 18°C.The plants were watered every day with tap water. Approximately 4 to 5 kg of fully expanded leaves were used for the isolation of mitochondria.Potato tubers (Solanum tuberosum L.) were obtained from a local market.In previous publications, Journet et al. (16) We also demonstrate that all the biotin present in the matrix space of the plant mitochondrion is associated 'Abbreviations: MCase, 3-methylcrotonyl-CoA carboxylase; PFP, PPi:fructose-6-phosphate-1 -phosphotransferase; GAPDH, glyceraldehyde-3-phosphate dehydrogenase. Preparation of MitochondriaMitochondria were isolated and purified from potato tubers as described by Douce et al. (6) by using self-generating Percoll gradients. The mitochondria were found in a broad brownred band near the bottom of the tube, whereas the "microsomal" fraction, containing the yellow envelope surrounding the amyloplasts, remained near the top of the tube. The mitochondria were subsequently concentrated by differential centrifugation. To remove all the contaminating peroxisomes the purification procedure was repeated once (i.e. a second time through Percoll). Under these conditions, we have verified that catalase activity with substrate concentrations up to 200 ,M was almost negligible.Mitochondria were isolated and purified from green pea leaves as described by Douce et al. (6), using self-generating Percoll gradients and a linear gradient of0 to 10% (w/v) PVP-25 (Kca 25, Serva) (top to bottom). The mitochondria were found in a tight white band near the bottom of the tube, whereas the thylakoids remained near the top of the tube. The mitochondria were subsequently concentrated by differential centrifugation. The ...

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Section: Discussionmentioning

confidence: 99%

Characterization of Biotin and 3-Methylcrotonyl-Coenzyme A Carboxylase in Higher Plant Mitochondria

Baldet¹,

Alban²,

Axiotis³

et al. 1992

Plant Physiol.

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“…Thc enzymatic reaction was initiated by the addition of CoASH. Aliquots of the reaction mixture were treated as described by Bushan et al (1986) and analyzed by HPLC, which was performed with slight modifications as described earlier (Gerbling and Gerhardt, 1988). HPLC was carried out by the use of a RP-18 Knauer column (250 X 4.6 mm).…”

Section: Coa-ester Separation On Reverse-phase Hplcmentioning

confidence: 99%

Biotin biosynthesis in higher plant cells

Baldet

Gerbling

Axiotis

et al. 1993

European Journal of Biochemistry

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Biotin biosynthesis was investigated in lavender cell cultures (Lavandula vera L.). Two different biological assays and two different HPLC procedures were used to identify all the intermediates involved in biotin biosynthesis. The pathway for biotin biosynthesis could be analyzed starting with [3H]pimelic acid as precursor, leading to labelled biotin and even to labelled biotinylated enzymes. Intermediates known from the bacterial pathway (7‐oxo‐8‐amino‐pelargonic acid, 7,8‐diamino‐pelargonic acid, dethiobiotin) were present in detectable amounts. Pimelic acid activation to pimeloyl‐CoA could be observed. In contrast to bacterial cells, an unknown stable labelled intermediate, named compound A, accumulated. This compound coeluted with an authentic sample of 9‐mercaptodethiobiotin from HPLC with an anion‐exchange column and was as effective as biotin in supporting the growth of the strain bioB105 of Escherichia coli. When 3H‐labelled compound A was added to the growth medium of the lavender cells it was incorporated in an acidomycin‐sensitive manner into biotin. [3H]Dethiobiotin was incorporated into both compound A and biotin. These results strongly suggest that, in higher plant cells, the reaction catalysed by biotin synthase may proceed in two distinct steps involving mercaptodethiobiotin (9‐mercaptodethiobiotin ?) as an intermediate.

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“…5). In vitro assays have demonstrated that BCAA are catabolized in isolated plant peroxisomes (9,10). However, several potential BCAA catabolic enzymes in Arabidopsis, pea, and soybean have been isolated from mitochondria or contain apparent mitochondrial transit signals (Fig.…”

Section: Functional Complementation Of Chy1 With a Human Hibyl-mentioning

confidence: 99%

“…The subcellular localization of BCAA catabolism in plants remains controversial. Although BCAA catabolism is mitochondrial in mammals, peroxisomes isolated from mung bean and sunflower cotyledons can convert labeled BCAAs to propionyl-CoA and acetyl-CoA (9,10).…”

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confidence: 99%

chy1, an Arabidopsis Mutant with Impaired β-Oxidation, Is Defective in a Peroxisomal β-Hydroxyisobutyryl-CoA Hydrolase

Zolman

Monroe-Augustus

Thompson

et al. 2001

Journal of Biological Chemistry

145

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The Arabidopsis chy1 mutant is resistant to indole-3-butyric acid, a naturally occurring form of the plant hormone auxin. Because the mutant also has defects in peroxisomal ␤-oxidation, this resistance presumably results from a reduced conversion of indole-3-butyric acid to indole-3-acetic acid. We have cloned CHY1, which appears to encode a peroxisomal protein 43% identical to a mammalian valine catabolic enzyme that hydrolyzes ␤-hydroxyisobutyryl-CoA. We demonstrated that a human ␤-hydroxyisobutyryl-CoA hydrolase functionally complements chy1 when redirected from the mitochondria to the peroxisomes. We expressed CHY1 as a glutathione S-transferase (GST) fusion protein and demonstrated that purified GST-CHY1 hydrolyzes ␤-hydroxyisobutyryl-CoA. Mutagenesis studies showed that a glutamate that is catalytically essential in homologous enoyl-CoA hydratases was also essential in CHY1. Mutating a residue that is differentially conserved between hydrolases and hydratases established that this position is relevant to the catalytic distinction between the enzyme classes. It is likely that CHY1 acts in peroxisomal valine catabolism and that accumulation of a toxic intermediate, methacrylyl-CoA, causes the altered ␤-oxidation phenotypes of the chy1 mutant. Our results support the hypothesis that the energy-intensive sequence unique to valine catabolism, where an intermediate CoA ester is hydrolyzed and a new CoA ester is formed two steps later, avoids methacrylyl-CoA accumulation.

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Oxidative Decarboxylation of Branched-Chain 2-Oxo Fatty Acids by Higher Plant Peroxisomes

Cited by 42 publications

References 11 publications

Characterization of Biotin and 3-Methylcrotonyl-Coenzyme A Carboxylase in Higher Plant Mitochondria

Characterization of Biotin and 3-Methylcrotonyl-Coenzyme A Carboxylase in Higher Plant Mitochondria

Biotin biosynthesis in higher plant cells

chy1, an Arabidopsis Mutant with Impaired β-Oxidation, Is Defective in a Peroxisomal β-Hydroxyisobutyryl-CoA Hydrolase

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