Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher Plants
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....
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2016-07-01
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| Series: | Frontiers in Plant Science |
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| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fpls.2016.01042/full |
| _version_ | 1819089940241186816 |
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| author | Abir U Igamberdiev Alexander T Eprintsev |
| author_facet | Abir U Igamberdiev Alexander T Eprintsev |
| author_sort | Abir U Igamberdiev |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-12-21T22:15:55Z |
| format | Article |
| id | doaj.art-308e47a4ed3240329650e370634653d7 |
| institution | Directory Open Access Journal |
| issn | 1664-462X |
| language | English |
| last_indexed | 2024-12-21T22:15:55Z |
| publishDate | 2016-07-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Plant Science |
| spelling | doaj.art-308e47a4ed3240329650e370634653d72022-12-21T18:48:26ZengFrontiers Media S.A.Frontiers in Plant Science1664-462X2016-07-01710.3389/fpls.2016.01042205704Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher PlantsAbir U Igamberdiev0Alexander T Eprintsev1Memorial University of NewfoundlandVoronezh State UniversityOrganic 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.http://journal.frontiersin.org/Journal/10.3389/fpls.2016.01042/fullOrganic acidstricarboxylic acid cyclefumarateCitrateoxalateMalate |
| spellingShingle | Abir U Igamberdiev Alexander T Eprintsev Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher Plants Frontiers in Plant Science Organic acids tricarboxylic acid cycle fumarate Citrate oxalate Malate |
| title | Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher Plants |
| title_full | Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher Plants |
| title_fullStr | Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher Plants |
| title_full_unstemmed | Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher Plants |
| title_short | Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher Plants |
| title_sort | organic acids the pools of fixed carbon involved in redox regulation and energy balance in higher plants |
| topic | Organic acids tricarboxylic acid cycle fumarate Citrate oxalate Malate |
| url | http://journal.frontiersin.org/Journal/10.3389/fpls.2016.01042/full |
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