伍德-隆達爾代謝途徑

伍德－隆達爾代謝途徑（Wood–Ljungdahl pathway）是一類為產醋酸鹽（英語：Acetogen）細菌跟產甲烷古菌所用的生物化學反應，這代謝途徑又被稱為還原性乙酰輔酶A 途徑。^[1]這反應使得生物體可用氫作為電子予體，以二氧化碳作為電子受體，並使得生物體能以之作為生物合成的基礎。

在這代謝途徑中，二氧化碳被還原成一氧化碳及甲酸，或直接被還原成醛，而這醛會再進一步地被還原成甲基並與一氧化碳和輔酶A反應生成乙酰輔酶A。

兩個特定的酵素會參與一氧化碳部分的途徑：一氧化碳脫氫酶和乙酰輔酶A連接酶（英語：Acetyl-CoA synthetase）。其中前者會催化二氧化碳的還原反應；而後者會將如此產生的一氧化碳與甲基連接以生成乙酰輔酶A。^[1]^[2]

一些厭氧的細菌和古菌也會使用逆向的伍德－隆達爾代謝途徑來分解乙酸鹽，像例如說一些產甲烷菌會將乙酸鹽分解為甲基與一氧化碳，並進一步將甲基給還原成甲烷，同時將一氧化碳給氧化成二氧化碳；^[3]另一方面，硫還原細菌（英語：Sulfate-reducing microorganism）會將乙酸鹽給完全氧化成氫氣與二氧化碳，與此同時將硫酸鹽給還原成硫化物。^[4]在逆向途徑中，乙酰輔酶A連接酶有時又被稱為乙酰輔酶A脫羧酶。

這途徑同時出現於產醋酸（英語：Acetogen）細菌跟產甲烷古菌當中^[5]；與逆向三羧酸循環（英語：Reverse Krebs cycle）與卡爾文循環不同的是，這反應並不是循環的。近期對一系列細菌和古菌的基因研究的研究發現，所有細胞生物的最後共祖可能是在熱液中使用伍德－隆達爾代謝途徑的生物；^[6]而對代謝途徑的系統發生重構也支持此點；^[7]然而在近期嘗試重現此類還原二氧化碳途徑的實驗中，只有非常少量（少於0.03mM）的丙酮酸鹽用自然鐵做還原劑^[8]；而在熱液環境中只有更少量的（大約10μM）用氫氣做還原劑。^[9]

參見

參考資料

^ ^1.0 ^1.1 Ragsdale Stephen W. Metals and Their Scaffolds To Promote Difficult Enzymatic Reactions. Chem. Rev. 2006, 106 (8): 3317–3337. PMID 16895330. doi:10.1021/cr0503153.
^ Paul A. Lindahl "Nickel-Carbon Bonds in Acetyl-Coenzyme A Synthases/Carbon Monoxide Dehydrogenases" Met. Ions Life Sci. 2009, volume 6, pp. 133–150. doi:10.1039/9781847559159-00133
^ Can, Mehmet; Armstrong, Fraser A.; Ragsdale, Stephen W. Structure, Function, and Mechanism of the Nickel Metalloenzymes, CO Dehydrogenase, and Acetyl-CoA Synthase. Chemical Reviews. 2014-04-23, 114 (8): 4149–4174. ISSN 0009-2665. PMC 4002135 . PMID 24521136. doi:10.1021/cr400461p.
^ Spormann, Alfred M.; Thauer, Rudolf K. Anaerobic acetate oxidation to CO₂ by Desulfotomaculum acetoxidans. Archives of Microbiology. 1988, 150 (4): 374–380. ISSN 0302-8933. S2CID 2158253. doi:10.1007/BF00408310.
^ Matschiavelli, N.; Oelgeschlager, E.; Cocchiararo, B.; Finke, J.; Rother, M. Function and regulation of isoforms of carbon monoxide dehydrogenase/acetyl-CoA synthase in Methanosarcina acetivorans. Journal of Bacteriology. 2012, 194 (19): 5377–87. PMC 3457241 . PMID 22865842. doi:10.1128/JB.00881-12.
^ M. C. Weiss; et al. The physiology and habitat of the last universal common ancestor. Nature Microbiology. 2016, 1 (16116): 16116. PMID 27562259. S2CID 2997255. doi:10.1038/nmicrobiol.2016.116.
^ Braakman, Rogier; Smith, Eric. The Emergence and Early Evolution of Biological Carbon-Fixation. PLOS Computational Biology. 2012-04-19, 8 (4): e1002455. Bibcode:2012PLSCB...8E2455B. ISSN 1553-7358. PMC 3334880 . PMID 22536150. doi:10.1371/journal.pcbi.1002455 （英語）.
^ Varma, Sreejith J.; Muchowska, Kamila B.; Chatelain, Paul; Moran, Joseph. Native iron reduces CO2 to intermediates and end-products of the acetyl-CoA pathway. Nature Ecology & Evolution. 2018-04-23, 2 (6): 1019–1024. ISSN 2397-334X. PMC 5969571 . PMID 29686234. doi:10.1038/s41559-018-0542-2 （英語）.
^ Preiner, Martina; Igarashi, Kensuke; Muchowska, Kamila B.; Yu, Mingquan; Varma, Sreejith J.; Kleinermanns, Karl; Nobu, Masaru K.; Kamagata, Yoichi; Tüysüz, Harun; Moran, Joseph; Martin, William F. A hydrogen-dependent geochemical analogue of primordial carbon and energy metabolism. Nature Ecology & Evolution. April 2020, 4 (4): 534–542 [2022-07-30]. ISSN 2397-334X. PMID 32123322. S2CID 211729738. doi:10.1038/s41559-020-1125-6. （原始內容存檔於2023-02-17）（英語）.

延伸閱讀

Wood HG. Life with CO or CO2 and H2 as a source of carbon and energy. FASEB J. February 1991, 5 (2): 156–63. PMID 1900793. S2CID 45967404. doi:10.1096/fasebj.5.2.1900793.
Diekert G, Wohlfarth G. Metabolism of homoacetogens. Antonie van Leeuwenhoek. 1994, 66 (1–3): 209–21. PMID 7747932. S2CID 7473300. doi:10.1007/BF00871640.

[Rags-1] 1.0 ^1.1 Ragsdale Stephen W. Metals and Their Scaffolds To Promote Difficult Enzymatic Reactions. Chem. Rev. 2006, 106 (8): 3317–3337. PMID 16895330. doi:10.1021/cr0503153.

[2] Paul A. Lindahl "Nickel-Carbon Bonds in Acetyl-Coenzyme A Synthases/Carbon Monoxide Dehydrogenases" Met. Ions Life Sci. 2009, volume 6, pp. 133–150. doi:10.1039/9781847559159-00133

[3] Can, Mehmet; Armstrong, Fraser A.; Ragsdale, Stephen W. Structure, Function, and Mechanism of the Nickel Metalloenzymes, CO Dehydrogenase, and Acetyl-CoA Synthase. Chemical Reviews. 2014-04-23, 114 (8): 4149–4174. ISSN 0009-2665. PMC 4002135 . PMID 24521136. doi:10.1021/cr400461p.

[4] Spormann, Alfred M.; Thauer, Rudolf K. Anaerobic acetate oxidation to CO₂ by Desulfotomaculum acetoxidans. Archives of Microbiology. 1988, 150 (4): 374–380. ISSN 0302-8933. S2CID 2158253. doi:10.1007/BF00408310.

[5] Matschiavelli, N.; Oelgeschlager, E.; Cocchiararo, B.; Finke, J.; Rother, M. Function and regulation of isoforms of carbon monoxide dehydrogenase/acetyl-CoA synthase in Methanosarcina acetivorans. Journal of Bacteriology. 2012, 194 (19): 5377–87. PMC 3457241 . PMID 22865842. doi:10.1128/JB.00881-12.

[6] M. C. Weiss; et al. The physiology and habitat of the last universal common ancestor. Nature Microbiology. 2016, 1 (16116): 16116. PMID 27562259. S2CID 2997255. doi:10.1038/nmicrobiol.2016.116.

[7] Braakman, Rogier; Smith, Eric. The Emergence and Early Evolution of Biological Carbon-Fixation. PLOS Computational Biology. 2012-04-19, 8 (4): e1002455. Bibcode:2012PLSCB...8E2455B. ISSN 1553-7358. PMC 3334880 . PMID 22536150. doi:10.1371/journal.pcbi.1002455 （英語）.

[8] Varma, Sreejith J.; Muchowska, Kamila B.; Chatelain, Paul; Moran, Joseph. Native iron reduces CO2 to intermediates and end-products of the acetyl-CoA pathway. Nature Ecology & Evolution. 2018-04-23, 2 (6): 1019–1024. ISSN 2397-334X. PMC 5969571 . PMID 29686234. doi:10.1038/s41559-018-0542-2 （英語）.

[9] Preiner, Martina; Igarashi, Kensuke; Muchowska, Kamila B.; Yu, Mingquan; Varma, Sreejith J.; Kleinermanns, Karl; Nobu, Masaru K.; Kamagata, Yoichi; Tüysüz, Harun; Moran, Joseph; Martin, William F. A hydrogen-dependent geochemical analogue of primordial carbon and energy metabolism. Nature Ecology & Evolution. April 2020, 4 (4): 534–542 [2022-07-30]. ISSN 2397-334X. PMID 32123322. S2CID 211729738. doi:10.1038/s41559-020-1125-6. （原始內容存檔於2023-02-17）（英語）.

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