[NiFe]-hydrogenases: spectroscopic and electrochemical definition of reactions and intermediates
[NiFe]-hydrogenases: spectroscopic and electrochemical definition of reactions and intermediates
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DOI：
10.1098/rsta.2004.1528
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发表时间：
2005-04-15
期刊：
影响因子：
5
通讯作者：
Albracht, PJ
中科院分区：
文献类型：
--
作者：
Armstrong, FA;Albracht, PJ
微生物中二氢 H-2 的产生和使用是由称为氢化酶的高活性“古老”金属酶催化的。根据活性位点金属原子的数量和特性，氢化酶分为三个主要类别：[NiFe]-、[FeFe]- 和 [Fe]-。所有这些都含有不寻常的配体CO（在大多数情况下还含有CN-），使它们成为“有机金属”辅助因子的有趣例子。这些配体使用红外光谱使活性位点高度“可见”，这补充了电子顺磁共振光谱在研究机制和识别中间体方面的使用。氢化酶正在成为未来能源技术研究的关注焦点，不仅包括燃料电池中的 H-2 生产，还包括 H-2 氧化。固定在电极上的氢化酶表现出高电催化活性，不仅为其研究提供了重要的新技术，而且为使用酶本身或启发合成催化剂的新型燃料电池奠定了基础。与铂电催化剂进行了有利的比较，酶的优势在于其对 H-2 的特异性和对 CO 的耐受性。利用氢化酶的一个挑战是它们对 O-2 的敏感性，但已知一些生物体产生的酶可以通过活性位点和气体进入通道的微妙改变来克服这个问题。
Production and usage of di-hydrogen, H-2, in micro-organisms is catalysed by highly active, 'ancient' metalloenzymes known as hydrogenases. Based on the number and identity of metal atoms in their active sites, hydrogenases fall into three main classes, [NiFe]-, [FeFe]- and [Fe]-. All contain the unusual ligand CO (and in most cases CN- as well) making them intriguing examples of 'organometallic' cofactors. These ligands render the active sites superbly 'visible' using infrared spectroscopy, which complements the use of electron paramagnetic resonance spectroscopy in studying mechanisms and identifying intermediates. Hydrogenases are becoming a focus of attention for research into future energy technologies, not only H-2 production but also H-2 oxidation in fuel cells. Hydrogenases immobilized on electrodes exhibit high electrocatalytic activity, providing not only an important new technique for their investigation, but also a basis for novel fuel cells either using the enzyme itself, or inspired synthetic catalysts. Favourable comparisons have been made with platinum electrocatalysts, an advantage of enzymes being their specificity for H-2 and tolerance of CO. A challenge for exploiting hydrogenases is their sensitivity to O-2, but some organisms are known to produce enzymes that overcome this problem by subtle alterations of the active site and gas access channels.