金属酵素の構造と作用 (生化学的立場から) について

概要

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One of the major functions of the essential metals in biological systems is their catalytic activities as metalloenzymes. In this section, discussions are mainly focused on the iron and copper enzymes. These transient metals are involved as cofactors in various enzymes or proteins, including oxidoreductases, oxygenases, electron carrier proteins, and oxygen carrier proteins. Much evidence suggest that there are three distinct states of copper in copper-containing enzymes, i. e., blue Cu (II), nonblue Cu (II), and diamagnetic Cu (II) -Cn (II) pair. The relation between the chemical state and biological function of the copper is discussed. Likewise, X-ray crystallographic analyses of the iron-containing electron carrier proteins, iron-sulfur proteins, reveal that there are three principal types of Fe-S clusters, namely, 1 Fe, 2 Fe-2S, and 4 Fe-4 S per center. Some of these clusters are also involved in various enzymes, such as xanthine oxidase, nitrogenase systems, hydrogenase, mitochondrial electron transport systems and so forth. In oxygenases too, iron and copper are the important cofactors ; most of dioxygenases as well as some of monooxygenases contain either iron or copper. The role of these transient metals in oxygenation reaction as a site of oxygen activation is also discussed.
社団法人有機合成化学協会の論文