Plant pyruvate dehydrogenase complexes

Luethy, Michael H.; Miernyk, Ján A.; David, Nancy R.; Randall, Douglas D.

doi:10.1007/978-3-0348-8981-0_5

Cited by 28 publications

(23 citation statements)

References 72 publications

(46 reference statements)

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“…The presence of two immunoreactive E2-like proteins from pea leaf mitochondria was first reported by Luethy et al (4). The potential for two E2 isoforms in plants was also demonstrated by the purification of pea 2 and potato (25) mitochondrial PDCs.…”

Section: Discussionmentioning

confidence: 80%

“…Indeed, these mitochondrial preparations from A. thaliana are contaminated with chloroplasts, judging by their green color. Highly purified pea mitochondrial PDC contains a 52-kDa E2 species as well as a faint immunoreactive species at 76 kDa, which is the position where the A. thaliana isoform 2 migrates (4,26). Coomassie Blue staining also reveals this protein in purified preparations but at levels considerably (2-fold) less than the 52-kDa species.…”

Section: Discussionmentioning

confidence: 98%

“…Both PDC isoforms probably provide acetylCoA for fatty acid biosynthesis, but a primary role of the mitochondrial isoform is to link glycolytic and tricarboxylic acid metabolism (reviewed in Ref. 4).…”

mentioning

confidence: 99%

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The Dihydrolipoamide S-Acetyltransferase Subunit of the Mitochondrial Pyruvate Dehydrogenase Complex from Maize Contains a Single Lipoyl Domain

Thelen¹,

Muszynski²,

David³

et al. 1999

Journal of Biological Chemistry

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Immunoanalysis of mitochondrial proteins from various plants, using a monoclonal antibody against the maize E2, revealed 50 -54-kDa cross-reacting polypeptides in all samples. A larger protein (76 kDa) was also recognized in an enriched pea mitochondrial PDC preparation, indicating two distinct E2s. The presence of a single lipoyl-domain E2 in Arabidopsis thaliana was confirmed by identifying a gene encoding a hypothetical protein with 62% amino acid identity to the maize homologue. These data suggest that all plant mitochondrial PDCs contain an E2 with a single lipoyl domain. Additionally, A. thaliana and other dicots possess a second E2, which contains two lipoyl domains and is only 33% identical at the amino acid level to the smaller isoform. The reason two distinct E2s exist in dicotyledon plants is uncertain, although the variability between these isoforms, particularly within the subunit-binding domain, suggests different roles in assembly and/or function of the plant mitochondrial PDC.

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Section: Discussionmentioning

confidence: 80%

Section: Discussionmentioning

confidence: 98%

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The Dihydrolipoamide S-Acetyltransferase Subunit of the Mitochondrial Pyruvate Dehydrogenase Complex from Maize Contains a Single Lipoyl Domain

Thelen¹,

Muszynski²,

David³

et al. 1999

Journal of Biological Chemistry

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“…Lipoamide dehydrogenase is part of the ␣-ketoacid dehydrogenase complexes, the pyruvate dehydrogenase complex (PDC; Luethy et al, 1996), the ␣-ketoglutarate dehydrogenase complex, and the branched-chain ␣-ketoacid dehydrogenase complex, as well as the Gly decarboxylase complex (GDC;Oliver, 1994). These multienzyme complexes consist of three to four subunits (component enzymes) that are in different stoichiometric arrangements noncovalently associated with each other.…”

mentioning

confidence: 99%

Characterization of Two cDNAs Encoding Mitochondrial Lipoamide Dehydrogenase from Arabidopsis

Lutziger

2001

Plant Physiology

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“…Plants have both mitochondrial and plastid PDC, and only mitochondrial PDC is regulated by phosphorylation [32]. Interestingly, activity of PDC in plants depends on light.…”

Section: Regulation Of Pdcmentioning

confidence: 99%

The biochemistry of the pyruvate dehydrogenase complex*

Patel

Korotchkina

2003

Biochem Molecular Bio Educ

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In the Westernized world the daily dietary caloric requirements are roughly provided as follows: 40% from carbohydrates, 40% from fats, and 20% from proteins. In some populations in developing countries the daily caloric contribution from carbohydrate is even higher due to its readily available sources and relatively low cost. Glucose, the principal product of carbohydrate digestion, passes through a series of enzymatic steps first in the non-oxidative glycolytic pathway (from glucose to pyruvate) followed by efficient oxidative metabolism via the tricarboxylic acid cycle (from acetyl-CoA to CO 2 and H 2 O) to harness a portion of its potential energy as ATP. Interestingly, these two major pathways are directly linked by the pyruvate dehydrogenase complex (PDC) 1 localized in the mitochondrial matrix (Fig. 1). In the fed state acetyl-CoA generated from pyruvate (derived mostly from glucose and some dietary amino acids) is also utilized for the biosynthesis of lipids such as long chain fatty acids and cholesterol by lipogenic tissues (such as liver and adipose tissues and under special conditions in mammary glands during lactation and in the brain during the prenatal and early postnatal development). Additionally, amino acids from excess dietary protein are metabolized by several specialized reactions or pathways generating intermediates that have to be ultimately converted to pyruvate first and then to acetylCoA via PDC either for complete oxidation to CO 2 and H 2 O or for lipogenesis. PDC is the only known reaction in most eukaryotes to generate acetyl-CoA (two-carbon compound) from pyruvate (three-carbon compound). Since this is a physiologically irreversible reaction and since there is no other known reaction or pathway to convert the two-carbon compound to pyruvate (or its equivalent) for the synthesis of glucose in animals, the flux through PDC is tightly regulated to meet the specific metabolic and energetic needs of different tissues during the fed and fasting (starvation) states. This is accomplished by covalent modification of the ratelimiting component of the complex involving sophisticated interplay among the components of the complex and allosteric modulations by acetyl-CoA and NADH, the products of the reaction (and also of fatty acid oxidation). It is evident from these simple considerations that PDC plays a key role as a gatekeeper of both caloric and glucose homeostasis in mammals. In this review, we will discuss recent developments concerning the structure-function relationship of this multienzyme complex from various organisms with emphasis on regulatory aspects of the mammalian complex. Detailed accounts of various aspects of this complex can be found in several excellent reviews [1][2][3][4][5][6][7][8][9][10][11]. STRUCTURE AND ORGANIZATION OF PDCPDC is present in most prokaryotic and eukaryotic organisms. It catalyzes several sequential reactions of oxidative decarboxylation of pyruvic acid by the action of its three catalytic components: (i) pyruvate dehydrogenase (E1) catalyzing the de...

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Plant pyruvate dehydrogenase complexes

Cited by 28 publications

References 72 publications

The Dihydrolipoamide S-Acetyltransferase Subunit of the Mitochondrial Pyruvate Dehydrogenase Complex from Maize Contains a Single Lipoyl Domain

The Dihydrolipoamide S-Acetyltransferase Subunit of the Mitochondrial Pyruvate Dehydrogenase Complex from Maize Contains a Single Lipoyl Domain

Characterization of Two cDNAs Encoding Mitochondrial Lipoamide Dehydrogenase from Arabidopsis

The biochemistry of the pyruvate dehydrogenase complex*

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