Young L J, Caughey W S
Biochemistry. 1986 Jan 14;25(1):152-61. doi: 10.1021/bi00349a022.
Cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1), as the terminal enzyme of the mammalian mitochondrial electron transport chain, has long been known to catalyze the reduction of dioxygen to water. We have found that when reductively activated in the presence of dioxygen, the enzyme will also catalyze the oxidation of carbon monoxide to its dioxide. Two moles of carbon dioxide is produced per mole of dioxygen, and similar rates of production are observed for 1- and 2-electron-reduced enzyme. If 13CO and O2 are used to initiate the reaction, then only 13CO2 is detected as a product. With 18O2 and 12CO, only unlabeled and singly labeled carbon dioxide are found. No direct evidence was obtained for a water-gas reaction (CO + H2O----CO2 + H2) of the oxidase with CO. The CO oxygenase activity is inhibited by cyanide, azide, and formate and is not due to the presence of bacteria. Studies with scavengers of partially reduced dioxygen show that catalase decreases the rate of CO oxygenation.
细胞色素c氧化酶（亚铁细胞色素c：氧氧化还原酶，EC 1.9.3.1）作为哺乳动物线粒体电子传递链的末端酶，长期以来一直被认为能催化将二氧还原为水。我们发现，当在二氧存在下进行还原激活时，该酶还能催化一氧化碳氧化为二氧化碳。每摩尔二氧产生两摩尔二氧化碳，对于单电子和双电子还原的酶，观察到类似的生成速率。如果用13CO和O2引发反应，那么仅检测到13CO2作为产物。使用18O2和12CO时，仅发现未标记和单标记的二氧化碳。未获得氧化酶与CO发生水煤气反应（CO + H2O----CO2 + H2）的直接证据。CO加氧酶活性受到氰化物、叠氮化物和甲酸盐的抑制，且不是由于细菌的存在。对部分还原二氧清除剂的研究表明，过氧化氢酶会降低CO氧化的速率。
