Aikazian V Ts, Nalbandian R M
Biokhimiia. 1977 Nov;42(11):2027-34.
From the peelings of cucumber Cucumis sativus and marrow squash Cucurbita pepo var. giramontia highly purified ascorbate oxidase preparations were obtained. Molecular weights, optical and EPR spectra, total copper contents and different type copper contents of the both proteins were similar. The effects of NaN3, KCN, I- and F- on the optical and EPR spectra of the proteins were studied. The incubation of ascorbate oxidase with these anions lead to the partial reduction of the copper. The data obtained indicate that F- is bound to the copper atoms of the type 2, and that N5- modifies surroundings of these copper atoms. The copper atoms of types 1 and 2 in both ascorbate oxidases, unlike fungal laccase, are completely reduced under effect of CN-. The bleaching of ascorbate oxidase, observed in alkaline media involves also increasing of the intensity of the band at 330 nm. The results show that three types of copper in ascorbate oxidase have various sensitivities to the inorganic anions. These data are compared with results observed for another blue copper-containing enzymes, such as laccases and ceruloplasmin.
从黄瓜（Cucumis sativus）和西葫芦（Cucurbita pepo var. giramontia）的外皮中获得了高度纯化的抗坏血酸氧化酶制剂。这两种蛋白质的分子量、光学和电子顺磁共振光谱、总铜含量以及不同类型的铜含量都相似。研究了NaN₃、KCN、I⁻和F⁻对这些蛋白质的光学和电子顺磁共振光谱的影响。抗坏血酸氧化酶与这些阴离子一起孵育会导致铜的部分还原。所得数据表明，F⁻与2型铜原子结合，而N₅⁻会改变这些铜原子的周围环境。与真菌漆酶不同，在CN⁻的作用下，两种抗坏血酸氧化酶中的1型和2型铜原子会完全还原。在碱性介质中观察到的抗坏血酸氧化酶的褪色还涉及330 nm处谱带强度的增加。结果表明，抗坏血酸氧化酶中的三种类型的铜对无机阴离子具有不同的敏感性。将这些数据与在其他含蓝色铜的酶（如漆酶和铜蓝蛋白）中观察到的结果进行了比较。
