Presence of a flavin semiquinone in methanol oxidase.
Presence of a flavin semiquinone in methanol oxidase.
复制标题
甲醇氧化酶中存在黄素半醌。
DOI：
10.1073/pnas.77.12.7099
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发表时间：
1980
影响因子：
11.1
通讯作者：
Abeles,RH
中科院分区：
文献类型：
--
作者：
Mincey,T;Tayrien,G;Mildvan,AS;Abeles,RH
多形汉逊酵母的甲醇氧化酶每八聚体含有五个“红色”黄素半醌和两个氧化黄素。底物的加入导致两种氧化黄素的还原，但不影响黄素半醌。增强的水质子弛豫速率表明，未配对电子的黄素半醌是可访问的溶剂和这种可访问性的自杀抑制剂环丙醇结合后显着降低。在天然酶中，半醌不能被空气氧化。所有的黄素从酶中分离出来，全酶通过加入氧化的黄素来重建。重组酶具有催化活性。酶的比活力为原酶的50%。得出的结论是，半醌是不需要的甲醇的氧化，虽然它可能存在于一个完整的网站，否则。
Methanol oxidase from Hansenula polymorpha contains five "red" flavin semiquinones and two oxidized flavins per octamer. Addition of substrate results in the reduction of the two oxidized flavins but does not affect the flavin semiquinones. Enhanced water proton relaxation rates indicate that the unpaired electron of the flavin semiquinones is accessible to the solvent and this accessibility is significantly decreased upon binding of the suicide inhibitor cyclopropanol. In the native enzyme, the semiquinones are not oxidizable by air. All flavins were resolved from the enzyme, and holoenzyme was reconstituted by addition of oxidized flavin. The reconstituted enzyme was catalytically active. The specific activity was 50% that of the original enzyme. It was concluded that the semiquinone is not required for the oxidation of methanol, although it may be present at an otherwise intact site.