氨基環丙烷羧酸氧化酶(EC 1.14.17.4)是一種酶,它可催化以下化學反應:
- 1-氨基環丙烷-1-羧酸 + 抗壞血酸 + O2 乙烯 + 氰化物 + 脫氫抗壞血酸 + CO2 + 2 H2O
該酶的3種底物是1-氨基環丙烷-1-羧酸(ACC)、抗壞血酸和氧氣,而其5種產物是乙烯、氰化物、脫氫抗壞血酸、二氧化碳和水。
該酶屬於氧化還原酶家族,特別是那些作用於配對供體的酶,以氧氣作為氧化劑並摻入或還原氧。摻入的氧不需要源自以還原的抗壞血酸作為一種供體的氧氣 ,並將一個氧原子摻入另一種供體中。該酶類的系統名稱是1-氨基環丙烷-1-羧酸加氧酶 (乙烯形成)。常用的其他名稱包括ACC氧化酶和乙烯形成酶。
結構研究
反應機制
機理和結構研究支持ACC和氧與位於ACC氧化酶活性位點的鐵中心結合。據信,結合的ACC的開環導致乙烯與不穩定的中間體氰基甲酸根離子一起消除,然後氰基甲酸根離子分解為氰離子和二氧化碳。氰離子是已知的含鐵酶的失活劑,但氰基甲酸根離子中間體被認為在將潛在有毒的氰化物帶離ACC氧化酶的活性位點方面發揮着至關重要的作用。最近在濃縮介質中發現氰基甲酸鹽是具有弱碳-碳鍵的四苯基鏻鹽。
參考資料
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- Pirrung MC. Ethylene biosynthesis from 1-aminocyclopropanecarboxylic acid. Acc. Chem. Res. 1999, 32 (8): 711–718. doi:10.1021/ar960003.
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- Murphy LJ, Robertson KN, Harroun SG, Brosseau CL, Werner-Zwanziger U, Moilanen J, Tuononen HM, Clyburne JA. A simple complex on the verge of breakdown: isolation of the elusive cyanoformate ion. Science. 2014, 344 (6179): 75–8. Bibcode:2014Sci...344...75M. PMID 24700853. S2CID 37086909. doi:10.1126/science.1250808.
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