2022 Fiscal Year Final Research Report
A New Metabolic Map: Does Non-enzymatic Carbon Metabolism Exist Within Cells
| Project/Area Number |
20K21294
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Review Section |
Medium-sized Section 38:Agricultural chemistry and related fields
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| Research Institution | Meiji University |
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Principal Investigator |
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| Project Period (FY) |
2020-07-30 – 2023-03-31
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| Keywords | クエン酸回路 / シアノバクテリア |
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| Outline of Final Research Achievements |
In vitro metabolic reconstruction studies have suggested that the citric acid cycle in cyanobacteria undergoes directional changes primarily influenced by pH (Ito et al., 2021, Plant J). This discovery implies that the citric acid cycle in cyanobacteria operates differently from typical organisms. Biochemical analyses revealed that the oxidation reaction activity of malate dehydrogenase is extremely weak. Further investigation of enzymes involved in malate metabolism showed that malic enzyme, which converts malate to pyruvate, exhibits significantly higher activity than malate dehydrogenase (Katayama et al., 2022, mBio). These results clearly indicate that the citric acid cycle in cyanobacteria is a specialized pathway (Katayama et al., 2022, mBio).
These findings highlight the unique characteristics and individuality of organisms, even in their typical primary metabolism within microalgae.
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| Free Research Field |
生化学
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| Academic Significance and Societal Importance of the Research Achievements |
シネコシスティスのクエン酸回路を中心に、複数の酵素を用いたin vitroの代謝再構成の実験が有効であることを示した。また、リンゴ酸デヒドロゲナーゼの生化学解析結果をもとに、シネコシスティスのクエン酸回路の特殊性を明らかにして、新しい代謝経路を発見した。この経路は、シネコシスティスのみならず、シアノバクテリア一般の経路であることも生化学的に示しており、代謝における高い保存性のある成果を得ることができた。また、真核微細藻類であるシアニディオシゾンメローラなどの酵素特性と比較すると、同じ微細藻類でも性質が異なることがわかった。このように、光合成生物の炭素代謝において、新しい視点を得ることができた。
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