Characterization of radicals in anaerobic degradation of benzoate, acytelene, and glycol ethers

在发酵和硫酸盐还原细菌中，苯甲酰辅酶a的还原转化是由一种不同于硝酸盐还原细菌的酶系统催化的。该反应生成环己烯羧基辅酶a，似乎不依赖于atp。第一步提出形成一个自由基羰基衍生物，随后被还原为环己烯羧基辅酶a。第二个项目涉及乙二醇醚的发酵降解，该降解应该通过类似于二醇脱水酶催化的反应的自由基机制进行。在第三个项目中，将研究含钼精素的酶乙炔水合酶在形成以钼精素为中心的自由基及其催化作用方面的作用。显然，在所有情况下，蛋白质和以底物为中心的自由基将通过EPR/ENDOR光谱识别，采用快速猝灭和自旋陷阱技术。

In fermenting and sulfate-reducing bacteria, the reductive transformation of benzoyl-CoA is catalyzed by an enzyme system different from that observed in nitrate-reducing bacteria. The reaction leads to cyclohexene carboxyl-CoA, and appears to be ATP-independent. Formation of a radical carbonyl derivative is proposed for the first step which is subsequently reduced to cyclohexene carboxyl-CoA. A second project deals with the fermentative degradation of ethylene glycol ethers which is supposed to proceed via a radical mechanism analogous to the reaction catalyzed by diol dehydratases. In a third project, the molybdopterin-containing enzyme acetylene hydratase will be investigated with respect to the formation of a pterin-centered radical and its role in catalysis. Clearly, in all cases protein and substrate centered radicals will be identified by EPR/ENDOR spectroscopy employing both rapid quench and spin trap techniques.