一氧化氮与抗坏血酸氧化酶的相互作用。

The interaction of nitric oxide with ascorbate oxidase.

Leeuwen F X, Wever R, Gelder B F, Avigliano L, Mondovi B

Biochim Biophys Acta. 1975 Oct 22;403(2):285-91. doi: 10.1016/0005-2744(75)90058-3.

Abstract

The reaction of nitric oxide with oxidized and reduced ascorbate oxidase (L-ascorbate: oxygen oxidoreductase, EC 1.10.3.3) has been investigated by optical absorption measurements and electron paramagnetic resonance, and the results are compared with those of ceruloplasmin. 2. Upon anaerobic incubation of oxidized ascorbate oxidase with nitric oxide a decrease of the absorbance at 610 nm is found, which is due to an electron transfer from nitric oxide to Type-1 copper. 3. In the presence of nitric oxide the EPR absorbance of ascorbate oxidase decreases and shows predominatly a signal with characteristics of Type-2 copper (g parallel = 2.248; A parallel = 188 G), whereas the type-1 copper signal has vanished. 4. Comparison of the intensities of the EPR signals before and after NO-treatment points to the presence of one Type-2 and three Type-1 copper atoms per molecule of ascorbate oxidase. 5. It is shown that the changes in the optical and the EPR spectrum of ascorbate oxidase induced by nitric oxide are reversible. No difference in enzymic activity is found between the native enzyme and the NO-treated enzyme after removal of nitric oxide.

摘要

通过光吸收测量和电子顺磁共振研究了一氧化氮与氧化型和还原型抗坏血酸氧化酶（L-抗坏血酸：氧氧化还原酶，EC 1.10.3.3）的反应，并将结果与铜蓝蛋白的结果进行了比较。2. 在厌氧条件下，将氧化型抗坏血酸氧化酶与一氧化氮一起孵育时，发现610 nm处的吸光度降低，这是由于一氧化氮向1型铜的电子转移所致。3. 在一氧化氮存在下，抗坏血酸氧化酶的电子顺磁共振吸光度降低，主要显示出具有2型铜特征的信号（g平行 = 2.248；A平行 = 188 G），而1型铜信号消失。4. 比较一氧化氮处理前后电子顺磁共振信号的强度表明，每分子抗坏血酸氧化酶存在一个2型铜原子和三个1型铜原子。5. 结果表明，一氧化氮诱导的抗坏血酸氧化酶的光学和电子顺磁共振光谱变化是可逆的。去除一氧化氮后，天然酶和经一氧化氮处理的酶之间未发现酶活性差异。