Activation of dihydrogen without transition metals

被引:37
作者
Berkessel, A [1 ]
机构
[1] Univ Cologne, Inst Organ Chem, D-50939 Cologne, Germany
关键词
D O I
10.1016/S1367-5931(00)00245-3
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The metal-free hydrogenase from methanogenic archaea (Hmd) is a unique enzyme: it catalyzes the reaction of its substrate, methenyl-tetrahydromethanopterin, with molecular hydrogen without the aid of a transition metal. In other words, Hmd is currently the only example of a purely organic hydrogenation catalyst. Recent results from various fields have shed new light on this enzyme. In biochemistry, there is experimental proof that a tightly bound (and metal-free) cofactor exists. Ab initio calculations have revealed that the concerted action of the Lewis-acidic substrate and a Bronsted-base appears to induce facile heterolysis of the hydrogen molecule. In chemical model studies, a transition-metal-free hydrogenation of ketones was achieved in the presence of catalytic base. Taken together, the experimental results available to date point to an enzymatic mechanism in which the hydrogen molecule is heterolyzed by the joint action of the Lewis-acidic substrate methenyl-tetrahydromethanopterin and a Bronsted-base in the active site (i.e. by bifunctional catalysis).
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页码:486 / 490
页数:5
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