1
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Cavanagh AP, Ort DR. Transgenic strategies to improve the thermotolerance of photosynthesis. PHOTOSYNTHESIS RESEARCH 2023; 158:109-120. [PMID: 37273092 DOI: 10.1007/s11120-023-01024-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 05/04/2023] [Indexed: 06/06/2023]
Abstract
Warming driven by the accumulation of greenhouse gases in the atmosphere is irreversible over at least the next century, unless practical technologies are rapidly developed and deployed at scale to remove and sequester carbon dioxide from the atmosphere. Accepting this reality highlights the central importance for crop agriculture to develop adaptation strategies for a warmer future. While nearly all processes in plants are impacted by above optimum temperatures, the impact of heat stress on photosynthetic processes stand out for their centrality. Here, we review transgenic strategies that show promise in improving the high-temperature tolerance of specific subprocesses of photosynthesis and in some cases have already been shown in proof of concept in field experiments to protect yield from high temperature-induced losses. We also highlight other manipulations to photosynthetic processes for which full proof of concept is still lacking but we contend warrant further attention. Warming that has already occurred over the past several decades has had detrimental impacts on crop production in many parts of the world. Declining productivity presages a rapidly developing global crisis in food security particularly in low income countries. Transgenic manipulation of photosynthesis to engineer greater high-temperature resilience holds encouraging promise to help meet this challenge.
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Affiliation(s)
- Amanda P Cavanagh
- School of Life Sciences, University of Essex, Colchester, CO4 3SQ, UK
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, 61801, USA
| | - Donald R Ort
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, 61801, USA.
- Departments of Plant Biology and Crop Sciences, University of Illinois, Urbana, IL, 61801, USA.
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2
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Bao H, Morency M, Rianti W, Saeheng S, Roje S, Weber APM, Walker BJ. Catalase protects against nonenzymatic decarboxylations during photorespiration in Arabidopsis thaliana. PLANT DIRECT 2021; 5:e366. [PMID: 34977450 PMCID: PMC8688901 DOI: 10.1002/pld3.366] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/22/2021] [Accepted: 11/23/2021] [Indexed: 05/16/2023]
Abstract
Photorespiration recovers carbon that would be otherwise lost following the oxygenation reaction of rubisco and production of glycolate. Photorespiration is essential in plants and recycles glycolate into usable metabolic products through reactions spanning the chloroplast, mitochondrion, and peroxisome. Catalase in peroxisomes plays an important role in this process by disproportionating H2O2 resulting from glycolate oxidation into O2 and water. We hypothesize that catalase in the peroxisome also protects against nonenzymatic decarboxylations between hydrogen peroxide and photorespiratory intermediates (glyoxylate and/or hydroxypyruvate). We test this hypothesis by detailed gas exchange and biochemical analysis of Arabidopsis thaliana mutants lacking peroxisomal catalase. Our results strongly support this hypothesis, with catalase mutants showing gas exchange evidence for an increased stoichiometry of CO2 release from photorespiration, specifically an increase in the CO2 compensation point, a photorespiratory-dependent decrease in the quantum efficiency of CO2 assimilation, increase in the 12CO2 released in a 13CO2 background, and an increase in the postillumination CO2 burst. Further metabolic evidence suggests this excess CO2 release occurred via the nonenzymatic decarboxylation of hydroxypyruvate. Specifically, the catalase mutant showed an accumulation of photorespiratory intermediates during a transient increase in rubisco oxygenation consistent with this hypothesis. Additionally, end products of alternative hypotheses explaining this excess release were similar between wild type and catalase mutants. Furthermore, the calculated rate of hydroxypyruvate decarboxylation in catalase mutant is much higher than that of glyoxylate decarboxylation. This work provides evidence that these nonenzymatic decarboxylation reactions, predominately hydroxypyruvate decarboxylation, can occur in vivo when photorespiratory metabolism is genetically disrupted.
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Affiliation(s)
- Han Bao
- Department of Energy‐Plant Research LaboratoryMichigan State UniversityEast LansingMIUSA
| | - Matt Morency
- Department of Energy‐Plant Research LaboratoryMichigan State UniversityEast LansingMIUSA
- Department of Plant BiologyMichigan State UniversityEast LansingMIUSA
| | - Winda Rianti
- Faculty of AgricultureUniversitas Singaperbangsa KarawangKarawangIndonesia
- Department of Plant ScienceWageningen UniversityWageningenThe Netherlands
| | - Sompop Saeheng
- Institute of Biological ChemistryWashington State UniversityPullmanWAUSA
| | - Sanja Roje
- Institute of Biological ChemistryWashington State UniversityPullmanWAUSA
| | - Andreas P. M. Weber
- Institute of Plant Biochemistry, Cluster of Excellence on Plant SciencesHeinrich‐Heine‐UniversityDüsseldorfGermany
| | - Berkley James Walker
- Department of Energy‐Plant Research LaboratoryMichigan State UniversityEast LansingMIUSA
- Department of Plant BiologyMichigan State UniversityEast LansingMIUSA
- Institute of Plant Biochemistry, Cluster of Excellence on Plant SciencesHeinrich‐Heine‐UniversityDüsseldorfGermany
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3
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Igamberdiev AU, Eprintsev AT. Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher Plants. FRONTIERS IN PLANT SCIENCE 2016; 7:1042. [PMID: 27471516 PMCID: PMC4945632 DOI: 10.3389/fpls.2016.01042] [Citation(s) in RCA: 183] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 07/04/2016] [Indexed: 05/18/2023]
Abstract
Organic acids are synthesized in plants as a result of the incomplete oxidation of photosynthetic products and represent the stored pools of fixed carbon accumulated due to different transient times of conversion of carbon compounds in metabolic pathways. When redox level in the cell increases, e.g., in conditions of active photosynthesis, the tricarboxylic acid (TCA) cycle in mitochondria is transformed to a partial cycle supplying citrate for the synthesis of 2-oxoglutarate and glutamate (citrate valve), while malate is accumulated and participates in the redox balance in different cell compartments (via malate valve). This results in malate and citrate frequently being the most accumulated acids in plants. However, the intensity of reactions linked to the conversion of these compounds can cause preferential accumulation of other organic acids, e.g., fumarate or isocitrate, in higher concentrations than malate and citrate. The secondary reactions, associated with the central metabolic pathways, in particularly with the TCA cycle, result in accumulation of other organic acids that are derived from the intermediates of the cycle. They form the additional pools of fixed carbon and stabilize the TCA cycle. Trans-aconitate is formed from citrate or cis-aconitate, accumulation of hydroxycitrate can be linked to metabolism of 2-oxoglutarate, while 4-hydroxy-2-oxoglutarate can be formed from pyruvate and glyoxylate. Glyoxylate, a product of either glycolate oxidase or isocitrate lyase, can be converted to oxalate. Malonate is accumulated at high concentrations in legume plants. Organic acids play a role in plants in providing redox equilibrium, supporting ionic gradients on membranes, and acidification of the extracellular medium.
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Affiliation(s)
- Abir U. Igamberdiev
- Department of Biology, Memorial University of Newfoundland, St. John’sNL, Canada
- *Correspondence: Abir U. Igamberdiev,
| | - Alexander T. Eprintsev
- Department of Biochemistry and Cell Physiology, Voronezh State UniversityVoronezh, Russia
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4
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Alhasawi A, Castonguay Z, Appanna ND, Auger C, Appanna VD. Glycine metabolism and anti-oxidative defence mechanisms in Pseudomonas fluorescens. Microbiol Res 2015; 171:26-31. [PMID: 25644949 DOI: 10.1016/j.micres.2014.12.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Revised: 11/25/2014] [Accepted: 12/07/2014] [Indexed: 12/22/2022]
Abstract
The role of metabolism in anti-oxidative defence is only now beginning to emerge. Here, we show that the nutritionally-versatile microbe, Pseudomonas fluorescens, reconfigures its metabolism in an effort to generate NADPH, ATP and glyoxylate in order to fend off oxidative stress. Glyoxylate was produced predominantly via the enhanced activities of glycine dehydrogenase-NADP(+) (GDH), glycine transaminase (GTA) and isocitrate lyase (ICL) in a medium exposed to hydrogen peroxide (H₂O₂). This ketoacid was utilized to produce ATP by substrate-level phosphorylation and to neutralize reactive oxygen species with the concomitant formation of formate. The latter was also a source of NADPH, a process mediated by formate dehydrogenase-NADP(+) (FDH). The increased activities of phosphoenolpyruvate carboxylase (PEPC) and pyruvate orthophosphate dikinase (PPDK) worked in tandem to synthesize ATP in the H₂O₂-challenged cells that had markedly diminished capacity for oxidative phosphorylation. These metabolic networks provide an effective means of combating ROS and reveal therapeutic targets against microbes resistant to oxidative stress.
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Affiliation(s)
- Azhar Alhasawi
- Faculty of Science and Engineering, Laurentian University, Sudbury, ON, Canada
| | - Zachary Castonguay
- Faculty of Science and Engineering, Laurentian University, Sudbury, ON, Canada
| | - Nishma D Appanna
- Faculty of Science and Engineering, Laurentian University, Sudbury, ON, Canada
| | - Christopher Auger
- Faculty of Science and Engineering, Laurentian University, Sudbury, ON, Canada
| | - Vasu D Appanna
- Faculty of Science and Engineering, Laurentian University, Sudbury, ON, Canada.
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5
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Photorespiratory Carbon and Nitrogen Cycling: Evidence from Studies of Mutant and Transgenic Plants. ACTA ACUST UNITED AC 2002. [DOI: 10.1007/0-306-48138-3_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
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6
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The mechanism of oxalate biosynthesis in higher plants: investigations with the stable isotopes
18
O and
13
C. ACTA ACUST UNITED AC 1997. [DOI: 10.1098/rspb.1982.0062] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Substantial incorporation of
18
O
2
into photorespiratory carbon oxidation cycle intermediates in illuminated
Spinacia oleracea
leaves confirms that oxygenase activity of the enzyme ribulose biphosphate carboxylase–oxygenase is a major source of glycollate in illuminated leaves. No
18
O
2
incorporation into oxalate was detected in these experiments, although
13
C incorporation from
13
CO
2
shows that oxalate synthesis is occurring under the experimental conditions. This result tends to minimize the role of a direct oxidation of glyoxylate derived (via phosphoglycollate and glycollate) from ribulose biphosphate oxygenase activity in oxalate synthesis in
Spinacia
. Measurements of δ
13
C show (in confirmation of earlier reports) that oxalate from
Spinacia
is less depleted in
13
C than is bulk organic C in the plant; it is possible the phosphoenolpyruvate carboxylase is involved in the production of the oxalate precursor. Of the plants tested,
Mercurialis
and
Pelargonium
shared with
Spinacia
the high δ
13
C value, while
Chenopodium
(closely related to
Spinacia
),
Oxalis
(more distantly related to
Pelargonium
) and two members of the Polygonaceae had oxalate δ
13
C values close to the whole-leaf δ
13
C value, which suggests derivation of both oxalate C atoms from carboxylase activity of the enzyme ribulose biphosphate carboxylase–oxygenase.
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7
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Gietl C. Malate dehydrogenase isoenzymes: cellular locations and role in the flow of metabolites between the cytoplasm and cell organelles. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1100:217-34. [PMID: 1610875 DOI: 10.1016/0167-4838(92)90476-t] [Citation(s) in RCA: 139] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Malate dehydrogenases belong to the most active enzymes in glyoxysomes, mitochondria, peroxisomes, chloroplasts and the cytosol. In this review, the properties and the role of the isoenzymes in different compartments of the cell are compared, with emphasis on molecular biological aspects. Structure and function of malate dehydrogenase isoenzymes from plants, mammalian cells and ascomycetes (yeast, Neurospora) are considered. Significant information on evolutionary aspects and characterisation of functional domains of the enzymes emanates from bacterial malate and lactate dehydrogenases modified by protein engineering. The review endeavours to give up-to-date information on the biogenesis and intracellular targeting of malate dehydrogenase isoenzymes as well as enzymes cooperating with them in the flow of metabolites of a given pathway and organelle.
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Affiliation(s)
- C Gietl
- Institute of Botany, Technical University of Munich, München, Germany
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8
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Yamaguchi J, Nishimura M, Akazawa T. Purification and characterization of heme-containing low-activity form of catalase from greening pumpkin cotyledons. EUROPEAN JOURNAL OF BIOCHEMISTRY 1986; 159:315-22. [PMID: 3758067 DOI: 10.1111/j.1432-1033.1986.tb09870.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In germinating pumpkin seeds, catalase is synthesized as a precursor (59-kDa) form, with molecular mass larger than the mature molecule (55 kDa). Both the precursor and mature forms of catalase are localized in the microbodies, i.e., glyoxysomes and leaf peroxisomes [Proc. Natl. Acad. Sci. USA 81, 4809-4813 (1984)]. We have now purified the 59-kDa catalase precursor and compared its properties with those of the 55-kDa mature molecule. The molar catalytic activity of the 59-kDa catalase was tenfold lower than that of the 55-kDa molecule, whereas the heme content was found to be same, with both forms containing four hematin groups per molecule. It is inferred from these results that the low activity of the 59-kDa molecule is not related to the binding of heme to the protein, but presumably involves conformational differences between the 59-kDa and 55-kDa molecules. We have further found that the reduction of total catalase activity in pumpkin cotyledons during greening was due to a decrease in the amount of the enzymically active 55-kDa catalase accompanying an increase in the 59-kDa molecule.
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9
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10
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Walton NJ. Glyoxylate decarboxylation during glycollate oxidation by pea leaf extracts: significance of glyoxylate and extract concentrations. PLANTA 1982; 155:218-224. [PMID: 24271770 DOI: 10.1007/bf00392719] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/1982] [Accepted: 03/07/1982] [Indexed: 06/02/2023]
Abstract
Hydrogen peroxide-dependent glyoxylate decarboxylation occurring during glycollate oxidation by pea leaf extracts (Pisum sativum L.) has been studied in relation to the effects of glyoxylate and extract concentration. With a saturating concentration of glycollate, decarboxylation was greatly stimulated by raising the glyoxylate concentration; at 30°C and with approx. 0.04 nkat of glycollate oxidase (as leaf extract) in the reaction mixture, CO2 release in the presence of 5 mM glycollate and 5 mM glyoxylate was equal to about 45% of glycollate oxidation. However, CO2 release at these substrate concentrations was not linearly proportional to the amount of extract supplied and was equal to a diminishing proportion of glycollate oxidation as the amount of extract was increased. This was shown to be due to the low affinity of catalase for H2O2, so that the endogenous catalase was able to destroy a larger proportion of the H2O2 generated at higher extract concentrations. It is argued that although at high glycoxylate concentrations (5-10 mM) in vitro, glyoxylate decarboxylation can be made to equal more than a third of the glycollate oxidised, less than 10% of the glyoxylate generated in vivo is likely to be decarboxylated in peroxisomes where high concentrations of glycollate oxidase and catalase are localised and where high concentrations of glyoxylate are unlikely to be maintained.
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Affiliation(s)
- N J Walton
- Department of Plant Biology, University of Newcastle upon Tyne, NE1 7RU, Newcastle upon Tyne, U.K
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11
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Behrends W, Rausch U, Löffler HG, Kindl H. Purification of glycollate oxidase from greening cucumber cotyledons. PLANTA 1982; 156:566-571. [PMID: 24272738 DOI: 10.1007/bf00392782] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/1982] [Accepted: 09/24/1982] [Indexed: 06/02/2023]
Abstract
Glycollate oxidase (glycollate: oxygen oxidoreductase, EC 1.1.3.1) was purified to apparent homogeneity from crude extracts of greening cucumber cotyledons (Cucumis sat vus). Molecular sieving and chromatofocusing resulted in 700-fold purification and specific activity of 1 μkat mg(-1) protein. The enzyme exhibited a Mr of 180,000, or 700,000, respectively, and is a tetramer or 16-mer made of identical subunits of Mr 43,000. Monospecific antibodies were raised against the homogeneous protein.
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Affiliation(s)
- W Behrends
- Biochemie, Fachbereich Chemie der Philipps-Universität, Lahnberge, D-3550, Marburg, Federal Republic of Germany
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12
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Regulation of Senescence of Excised Leaves of Some C3 and C4 Species by Endogenous H2O2. ACTA ACUST UNITED AC 1982. [DOI: 10.1016/s0015-3796(82)80034-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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14
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Walton NJ, Butt VS. Metabolism and decarboxylation of glycollate and serine in leaf peroxisomes. PLANTA 1981; 153:225-231. [PMID: 24276825 DOI: 10.1007/bf00383891] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/1981] [Accepted: 07/15/1981] [Indexed: 06/02/2023]
Abstract
The linked utilization of glycollate and L-serine has been studied in peroxisomal preparations from leaves of spinach beet (Beta vulgaris L.). The generation of glycine from glycollate was found to be balanced by the production of hydroxypyruvate from serine and similarly by 2-oxoglutarate when L-glutamate was substituted for L-serine. In the presence of L-malate and catalytic quantities of NAD(+), about 40% of the hydroxypyruvate was converted further to glycerate, whereas with substrate quantities of NADH, this conversion was almost quantitative. CO2 was released from the carboxyl groups of both glycollate and serine. Since the decarboxylation of both substrates was greatly in creased by the catalase inhibitor, 3-amino-1,2,4-triazole, and abolished by bovine liver catalase, it was attributed to the nonenzymic attack of H2O2, generated in glycollate oxidation, upon glyoxylate and hydroxypyruvate respectively. At 25-30° C, about 10% of the glyoxylate and hydroxypyruvate accumulated was decarboxylated, and the release of CO2 from each keto-acid was related to the amounts present. It is suggested that hydroxypyruvate decarboxylation might contribute significantly to photorespiration and provide a metabolic route for the complete oxidation of glycollate, the magnitude of this contribution depending upon the concentrations of glyoxylate and hydroxypyruvate in the peroxisomes.
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Affiliation(s)
- N J Walton
- Botany School, Oxford University, South Parks Road, OX1 3RA, Oxford, U.K
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15
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Walton NJ, Butt VS. Glutamate and serine as competing donors for amination of glyoxylate in leaf peroxisomes. PLANTA 1981; 153:232-237. [PMID: 24276826 DOI: 10.1007/bf00383892] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/1981] [Accepted: 07/15/1981] [Indexed: 06/02/2023]
Abstract
When provided with glycollate, peroxisomal extracts of leaves of spinach beet (Beta vulgaris L. cv.) converted L-serine and L-glutamate to hydroxypyruvate and 2-oxoglutarate respectively. When approximately saturating concentrations of each of these amino acids were incubated separately with glycollate, the utilization of serine was greater than that of glutamate. The utilization of glutamate was substantially reduced by the presence of relatively low concentrations of serine in the reaction mixture, whereas even high concentrations of glutamate caused only small reductions in serine utilization. Over the entire range of concentrations of amino acids examined, serine was invariably the preferred amino-group donor, but this preference was abolished at higher concentrations of glyoxylate. Serine not only competed favourably for glyoxylate but also inhibited L-glutamate: glyoxylate aminotransferase (GGAT), the degree of inhibition depending upon the glyoxylate concentration. Studies of L-serine: glyoxylate aminotransferase (SGAT) and GGAT in partially purified extracts from spinach-beet leaves confirmed that serine competitively inhibited GGAT but glutamate did not affect SGAT. Both enzymes were inhibited by high glyoxylate concentrations, the inhibition being relieved by suitably high concentrations of the appropriate amino acid. It is concluded that at the low glyoxylate concentrations likely to occur in vivo, the preferential utilization of serine would ensure flux through the glycollate pathway to glycerate, but at higher concentrations of glyoxylate, both enzymes could be fully active in glyoxylate amination.
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Affiliation(s)
- N J Walton
- Department of Plant Biology, University of Newcastle upon Tyne, NE1 7RU, Newcastle upon Tyne, U.K
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16
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Lüttge U, Fischer K. Light-dependent net CO-evolution by C3 and C 4 plants. PLANTA 1980; 149:59-63. [PMID: 24306193 DOI: 10.1007/bf00386228] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/1979] [Accepted: 01/20/1980] [Indexed: 06/02/2023]
Abstract
Light-dependent CO-evolution by the green leaves of C3 and C4 plants depends on the CO2/O2 ratio in the ambient atmosphere. This and other physiological responses suggest that CO-evolution is a byproduct of photorespiration. At CO2/O2 ratios up to 10(-3), the ratio of CO evolved: CO2 fixed in photosynthesis is significantly higher in C3 than in C4 plants. This discrepancy disappears when a correction is made for the CO2-concentrating mechanism in C4 photosynthesis, by which CO2-concentration at the site of ribulose-bis-phosphate carboxylase/oxygenase in the bundle sheaths is raised significantly as compared to the ambient atmosphere. Since the oxygenase function of this enzyme is responsible for glycolate synthesis, i.e., the substrate of photorespiration, this result seems to support the conclusion that CO-evolution is a consequence of photorespiration. CO-evolution may turn out to be a useful and rather straightforward indicator for photorespiration in ecophysiological studies.
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Affiliation(s)
- U Lüttge
- Institut für Botanik, Technische Hochschule Darmstadt, Schnittspahnstraße 3-5, D-6100, Darmstadt, Federal Republic of Germany
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17
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Parameters of the Reductive Pentose Phosphate Cycle and of the Glycolate Pathway under Different Concentrations of Oxygen. ACTA ACUST UNITED AC 1979. [DOI: 10.1016/s0044-328x(79)80235-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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18
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Uotila L, Koivusalo M. Purification of formaldehyde and formate dehydrogenases from pea seeds by affinity chromatography and S-formylglutathione as the intermediate of formaldehyde metabolism. Arch Biochem Biophys 1979; 196:33-45. [PMID: 574372 DOI: 10.1016/0003-9861(79)90548-4] [Citation(s) in RCA: 69] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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19
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Halliwell B. The chloroplast at work. A review of modern developments in our understanding of chloroplast metabolism. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1979; 33:1-54. [PMID: 415334 DOI: 10.1016/0079-6107(79)90024-5] [Citation(s) in RCA: 79] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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20
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Günther G, Baumann G, Klos J, Balfanz J. Nettophotosynthese und Photorespiration bei Zuckerrübe (Beta vulgaris) und Weißem Gänsefuß (Chenopodium album) unter dem Einfluß von Inhibitoren und Herbiziden. ACTA ACUST UNITED AC 1979. [DOI: 10.1016/s0015-3796(17)30615-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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21
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Grodzinski B. Glyoxylate decarboxylation during photorespiration. PLANTA 1978; 144:31-7. [PMID: 24408641 DOI: 10.1007/bf00385004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/1978] [Accepted: 06/09/1978] [Indexed: 05/08/2023]
Abstract
At 25° C under aerobic conditions with or without gluamate 10% of the [1-(14)C]glycollate oxidised in spinach leaf peroxisomes was released as (14)CO2. Without glutamate only 5% of the glycollate was converted to glycine, but with it over 80% of the glycollate was metabolised to glycine. CO2 release was probably not due to glycine breakdown in these preparations since glycine decarboxylase activity was not detected. Addition of either unlabelled glycine or isonicotinyl hydrazide (INH) did not reduce (14)CO2 release from either [1-(14)C]glycollate or [1-(14)C]glyoxylate. Furthermore, the amount of "available H2O2" (Grodzinski and Butt, 1976) was sufficient to account for all of the CO2 release by breakdown of glyoxylate. Peroxisomal glycollate metabolism was unaffected by light and isolated leaf chloroplasts alone did not metabolise glycollate. However, in a mixture of peroxisomes and illuminated chloroplasts the rate of glycollate decarboxylation increased three fold while glycine synthesis was reduced by 40%. Although it was not possible to measure "available H2O2" directly, the data are best explained by glyoxylate decarboxylation. Catalase reduced CO2 release and enhanced glycine synthesis. In addition, when a model system in which an active preparation of purified glucose oxidase generating H2O2 at a known rate was used to replace the chloroplasts, similar rates of (14)CO2 release and [(14)C]glycine synthesis from [1-(14)C]glycollate were measured. It is argued that in vivo glyoxylate metabolism in leaf peroxisomes is a key branch point of the glycollate pathway and that a portion of the photorespired CO2 arises during glyoxylate decarboxylation under the action of H2O2. The possibility that peroxisomal catalase exerts a peroxidative function during this process is discussed.
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Affiliation(s)
- B Grodzinski
- Department of Botany, Botany School, University of Cambridge, CB2 3EA, Cambridge, U.K
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22
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Grodzinski B, Butt VS. The effect of temperature on glycollate decarboxylation in leaf peroxisomes. PLANTA 1977; 133:261-6. [PMID: 24425260 DOI: 10.1007/bf00380687] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/1976] [Accepted: 09/27/1976] [Indexed: 05/08/2023]
Abstract
[1-(14)C]glycollate was oxidised to(14)CO2 by peroxisomes isolated from leaves of spinach beet about 3 times as rapidly at 35°C as at 25°C; the rate was further increased with rise in temperature to a maximum at 55°C. These increases are shown to be mainly due to the increased H2O2 available to oxidise glyoxylate non-enzymically as a result of the higher temperature coefficient of glycollate oxidase activity relative to that of catalase. These results are compared with similar increases in the rate of(14)CO2 release between 25°C and 35°C when [1-(14)C]glycollate was supplied to leaf discs in light or darkness. The role of these reactions in accounting for the temperature effect on the release of photorespiratory CO2 is discussed.
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Affiliation(s)
- B Grodzinski
- Botany School, Oxtord University, South Parks Road, OXI 3RA, Oxford, UK
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