Acetyl‐CoA carboxylase: a rapid novel assay procedure used in conjunction with the preparation of enzyme from maize leaves

Howard, Joy L.; Ridley, Stuart M.

doi:10.1016/0014-5793(90)80567-3

Cited by 24 publications

(15 citation statements)

References 17 publications

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“…We conclude that the major component of the ACCase activity in wheat germ represents the plastid enzyme. Two peaks of ACCase activity were observed after ion-exchange chromatography of maize protein (19). In that experiment, activity in the first minor peak was not inhibited by fluazifop (50 M), but activity in the major peak was.…”

Section: Resultsmentioning

confidence: 90%

Wheat cytosolic acetyl-CoA carboxylase complements an ACC1 null mutation in yeast

Joachimiak

Tevzadze

Podkowiński

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

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Spores harboring an ACC1 deletion derived from a diploid Saccharomyces cerevisiae strain, in which one copy of the entire ACC1 gene is replaced with a LEU2 cassette, fail to grow. A chimeric gene consisting of the yeast GAL10 promoter, yeast ACC1 leader, wheat cytosolic acetyl-CoA carboxylase (ACCase) cDNA, and yeast ACC1 3 tail was used to complement a yeast ACC1 mutation. The complementation demonstrates that active wheat ACCase can be produced in yeast. At low concentrations of galactose, the activity of the ''wheat gene'' driven by the GAL10 promoter is low and ACCase becomes limiting for growth, a condition expected to enhance transgenic yeast sensitivity to wheat ACCase-specific inhibitors. An aryloxyphenoxypropionate and two cyclohexanediones do not inhibit growth of haploid yeast strains containing the yeast ACC1 gene, but one cyclohexanedione inhibits growth of the gene-replacement strains at concentrations below 0.2 mM. In vitro, the activity of wheat cytosolic ACCase produced by the gene-replacement yeast strain is inhibited by haloxyfop and cethoxydim at concentrations above 0.02 mM. The activity of yeast ACCase is less affected. The wheat plastid ACCase in wheat germ extract is inhibited by all three herbicides at concentrations below 0.02 mM. Yeast gene-replacement strains will provide a convenient system for the study of plant ACCases.Acetyl-CoA carboxylase (ACCase) catalyzes the first committed step in de novo fatty acid biosynthesis and provides malonyl-CoA for the synthesis of very-long-chain fatty acids and a variety of important secondary metabolites, and for malonylation. In plants, these primary and secondary metabolic pathways are located in plastids and cytoplasm, respectively. Plants have two forms of ACCase (reviewed in ref.

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Section: Resultsmentioning

confidence: 90%

Wheat cytosolic acetyl-CoA carboxylase complements an ACC1 null mutation in yeast

Joachimiak

Tevzadze

Podkowiński

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

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“…The amount of labeled 4-hydroxybenzoate formed was calculated from the amount of fixed radioactivity by taking into account the known specific radioactivity of the total bicarbonate added to the assay mixture. The net carboxylation of phenylphosphate to 4-hydroxybenzoate could also be measured indirectly by measuring phosphate release (34,36). To reduce background values because of the nonspecific reaction of the phosphate detection reagent, the concentration of phenylphosphate added to the assay mixture was reduced to 0.5 mM, and only 15 to 30 g of protein was added.…”

Section: Methodsmentioning

confidence: 99%

Phenylphosphate Carboxylase: a New C-C Lyase Involved in Anaerobic Phenol Metabolism in Thauera aromatica

2004

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The anaerobic metabolism of phenol in the beta-proteobacterium Thauera aromatica proceeds via carboxylation to 4-hydroxybenzoate and is initiated by the ATP-dependent conversion of phenol to phenylphosphate. The subsequent para carboxylation of phenylphosphate to 4-hydroxybenzoate is catalyzed by phenylphosphate carboxylase, which was purified and studied. This enzyme consists of four proteins with molecular masses of 54, 53, 18, and 10 kDa, whose genes are located adjacent to each other in the phenol gene cluster which codes for phenol-induced proteins. Three of the subunits (54, 53, and 10 kDa) were sufficient to catalyze the exchange of 14 CO 2 and the carboxyl group of 4-hydroxybenzoate but not phenylphosphate carboxylation. Phenylphosphate carboxylation was restored when the 18-kDa subunit was added. The following reaction model is proposed. The 14 CO 2 exchange reaction catalyzed by the three subunits of the core enzyme requires the fully reversible release of CO 2 from 4-hydroxybenzoate with formation of a tightly enzyme-bound phenolate intermediate. Carboxylation of phenylphosphate requires in addition the 18-kDa subunit, which is thought to form the same enzyme-bound energized phenolate intermediate from phenylphosphate with virtually irreversible release of phosphate. The 54-and 53-kDa subunits show similarity to UbiD of Escherichia coli, which catalyzes the decarboxylation of a 4-hydroxybenzoate derivative in ubiquinone (ubi) biosynthesis. They also show similarity to components of various decarboxylases acting on aromatic carboxylic acids, such as 4-hydroxybenzoate or vanillate, whereas the 10-kDa subunit is unique. The 18-kDa subunit belongs to a hydratase/ phosphatase protein family. Phenylphosphate carboxylase is a member of a new family of carboxylases/ decarboxylases that act on phenolic compounds, use CO 2 as a substrate, do not contain biotin or thiamine diphosphate, require K ؉ and a divalent metal cation (Mg 2؉ or Mn 2؉ ) for activity, and are strongly inhibited by oxygen.The anaerobic metabolism of phenol has been studied to some extent in the beta-proteobacterium Thauera aromatica. The two initial steps of the pathway consist of the phosphorylation of phenol to phenylphosphate and the carboxylation of phenylphosphate to 4-hydroxybenzoate (36-38) (Fig. 1). Both enzyme activities are induced in cells grown anoxically on phenol and nitrate and not in cells grown on 4-hydroxybenzoate, the product of this process. 4-Hydroxybenzoate is also an intermediate in the metabolism of p-cresol (53)Further metabolism of 4-hydroxybenzoate proceeds via benzoyl coenzyme A (benzoyl-CoA) in two steps (Fig. 1). A specific CoA ligase forms 4-hydroxybenzoyl-CoA (7, 25), which is reductively dehydroxylated to benzoyl-CoA by a molybdoflavo-iron-sulfur protein, 4-hydroxybenzoyl-CoA reductase (13,15,26). The electron donor is a 2-[4Fe/4S] ferredoxin which is reduced by 2-oxoglutarate-ferredoxin oxidoreductase (21). Benzoyl-CoA is a common intermediate in the metabolism of many aromatic compounds. It is reductively d...

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“…Inorganic phosphate released in enzymatic assays was determined using the modified malachite green-ammonium molybdate assay (22).…”

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confidence: 99%

Insights into the Autotrophic CO ₂ Fixation Pathway of the Archaeon Ignicoccus hospitalis : Comprehensive Analysis of the Central Carbon Metabolism

et al. 2007

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Ignicoccus hospitalis is an autotrophic hyperthermophilic archaeon that serves as a host for another parasitic/ symbiotic archaeon, Nanoarchaeum equitans. In this study, the biosynthetic pathways of I. hospitalis were investigated by in vitro enzymatic analyses, in vivo 13 C-labeling experiments, and genomic analyses. Our results suggest the operation of a so far unknown pathway of autotrophic CO 2 fixation that starts from acetyl-coenzyme A (CoA). The cyclic regeneration of acetyl-CoA, the primary CO 2 acceptor molecule, has not been clarified yet. In essence, acetyl-CoA is converted into pyruvate via reductive carboxylation by pyruvateferredoxin oxidoreductase. Pyruvate-water dikinase converts pyruvate into phosphoenolpyruvate (PEP), which is carboxylated to oxaloacetate by PEP carboxylase. An incomplete citric acid cycle is operating: citrate is synthesized from oxaloacetate and acetyl-CoA by a (re)-specific citrate synthase, whereas a 2-oxoglutarateoxidizing enzyme is lacking. Further investigations revealed that several special biosynthetic pathways that have recently been described for various archaea are operating. Isoleucine is synthesized via the uncommon citramalate pathway and lysine via the ␣-aminoadipate pathway. Gluconeogenesis is achieved via a reverse Embden-Meyerhof pathway using a novel type of fructose 1,6-bisphosphate aldolase. Pentosephosphates are formed from hexosephosphates via the suggested ribulose-monophosphate pathway, whereby formaldehyde is released from C-1 of hexose. The organism may not contain any sugar-metabolizing pathway. This comprehensive analysis of the central carbon metabolism of I. hospitalis revealed further evidence for the unexpected and unexplored diversity of metabolic pathways within the (hyperthermophilic) archaea.

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Acetyl‐CoA carboxylase: a rapid novel assay procedure used in conjunction with the preparation of enzyme from maize leaves

Cited by 24 publications

References 17 publications

Wheat cytosolic acetyl-CoA carboxylase complements an ACC1 null mutation in yeast

Wheat cytosolic acetyl-CoA carboxylase complements an ACC1 null mutation in yeast

Phenylphosphate Carboxylase: a New C-C Lyase Involved in Anaerobic Phenol Metabolism in Thauera aromatica

Insights into the Autotrophic CO ₂ Fixation Pathway of the Archaeon Ignicoccus hospitalis : Comprehensive Analysis of the Central Carbon Metabolism

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Acetyl‐CoA carboxylase: a rapid novel assay procedure used in conjunction with the preparation of enzyme from maize leaves

Cited by 24 publications

References 17 publications

Wheat cytosolic acetyl-CoA carboxylase complements an ACC1 null mutation in yeast

Wheat cytosolic acetyl-CoA carboxylase complements an ACC1 null mutation in yeast

Phenylphosphate Carboxylase: a New C-C Lyase Involved in Anaerobic Phenol Metabolism in Thauera aromatica

Insights into the Autotrophic CO 2 Fixation Pathway of the Archaeon Ignicoccus hospitalis : Comprehensive Analysis of the Central Carbon Metabolism

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Insights into the Autotrophic CO ₂ Fixation Pathway of the Archaeon Ignicoccus hospitalis : Comprehensive Analysis of the Central Carbon Metabolism