3,3,3-Trifluoro-1,2-propanediol undergoes complete defluorination in two distinct steps: first, the conversion into 3,3,3-trifluoropropionaldehyde catalyzed by adenosylcobalamin (coenzyme B12)-dependent diol dehydratase; second, non-enzymatic elimination of all three fluorides from this aldehyde to afford malonic semialdehyde (3-oxopropanoic acid), which is decarboxylated to acetaldehyde. Diol dehydratase accepts 3,3,3-trifluoro-1,2-propanediol as a relatively poor substrate, albeit without significant mechanism-based inactivation of the enzyme during catalysis. Optical and EPR spectra revealed the steady-state formation of cob(II)alamin and a substrate-derived intermediate organic radical (3,3,3-trifluoro-1,2-dihydroxyprop-1-yl). The coenzyme undergoes Co-C bond homolysis initiating a sequence of reaction by the generally accepted pathway via intermediate radicals. However, the greater steric size of trifluoromethyl and especially its negative impact on the stability of an adjacent radical center compared to a methyl group has implications for the mechanism of the diol dehydratase reaction. Nevertheless, 3,3,3-trifluoropropionaldehyde is formed by the normal diol dehydratase pathway, but then undergoes non-enzymatic conversion into acetaldehyde, probably via 3,3-difluoropropenal and malonic semialdehyde.

中文翻译：

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辅酶 B12 依赖性二醇脱水酶对 3,3,3-三氟-1,2-丙二醇的作用导致消除所有氟化物并形成乙醛


3,3,3-三氟-1,2-丙二醇通过两个不同的步骤进行完全脱氟：首先，在腺苷钴胺素（辅酶 B12）依赖性二醇脱水酶的催化下转化为 3,3,3-三氟丙醛；第二，非酶法消除该醛中的所有三种氟化物，得到丙二酸半醛（3-氧代丙酸），其脱羧为乙醛。二醇脱水酶接受 3,3,3-三氟-1,2-丙二醇作为相对较差的底物，尽管在催化过程中没有明显的基于机制的酶失活。光学和 EPR 光谱揭示了钴（II​​）胺和底物衍生的中间体有机自由基（3,3,3-三氟-1,2-二羟基丙-1-基）的稳态形成。辅酶经历 Co-C 键均裂，通过中间自由基通过普遍接受的途径启动一系列反应。然而，与甲基相比，三氟甲基的空间尺寸更大，尤其是其对相邻自由基中心稳定性的负面影响，对二醇脱水酶反应的机制有影响。然而，3,3,3-三氟丙醛是通过正常的二醇脱水酶途径形成的，但随后可能通过3,3-二氟丙烯醛和丙二酸半醛进行非酶促转化为乙醛。