"Two-Step" Chronoamperometric Method for Studying the Anaerobic Inactivation of an Oxygen Tolerant NiFe Hydrogenase
"Two-Step" Chronoamperometric Method for Studying the Anaerobic Inactivation of an Oxygen Tolerant NiFe Hydrogenase
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DOI：
10.1021/ja910685j
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发表时间：
2010-04-07
影响因子：
15
通讯作者：
Leger, Christophe
中科院分区：
文献类型：
--
作者：
Fourmond, Vincent;Infossi, Pascale;Leger, Christophe
氢化酶催化H-2的氧化和生成。如果它们能够抵抗O-2的抑制，则可以用于生物技术装置，这促使了对它们失活机制的研究。直接电化学在这方面已经得到了充分的应用，但通常是以定性的方式。我们提出了一种新的精确计时电流法来研究氢化酶的厌氧失活机制，并将其应用于水蛭耐氧NiFe酶。我们证明伏安数据不能用于测量所谓NiB非活性态的还原电位，即使在小扫描速率限制下。我们发现，标准的（氧敏感的）NiFe加氢酶的失活机制并不适用于来自风草的酶。特别是，激活和失活反应不能遵循相同的反应途径。
Hydrogenases catalyze the oxidation and production of H-2. The fact that they could be used in biotechnological devices if they resisted inhibition by O-2 motivates the current research on their inactivation mechanism. Direct electrochemistry has been thoroughly used in this respect but often in a qualitative manner. We propose a new and precise chronoamperometric method for studying the anaerobic inactivation mechanism of hydrogenase, which we apply to the oxygen-tolerant NiFe enzyme from Aquifex aeolicus. We demonstrate that the voltammetric data cannot be used for measuring the reduction potential of the so-called NiB inactive state, even in the small scan rate limit. We show that the inactivation mechanism proposed for standard (oxygen-sensitive) NiFe hydrogenases does not apply in the case of the enzyme from A. aeolicus. In particular, the activation and inactivation reactions cannot follow the same reaction pathway.