Kakutani T, Watanabe H, Arima K, Beppu T
J Biochem. 1981 Feb;89(2):463-72. doi: 10.1093/oxfordjournals.jbchem.a133221.
A blue protein with a molecule weight of 12,000 containing 1 atom of type I Cu2+ was purified and crystallized from a denitrifying bacterium, Alcaligenes faecalis strain S-6, as an inactivating factor for copper-containing nitrite reductase of the same organism. Inactivation of the enzyme occurred when the enzyme was incubated aerobically with a catalytic amount of the blue protein in the presence of reducing agents such as cysteine and ascorbate. The blue protein acts as a direct electron donor for the enzyme to catalyze the reduction of nitrite, but in the absence of nitrite, the enzyme-reduced blue protein system reacts with oxygen to produce H2O2. A suicide inactivation mechanism of the enzyme due to this H2O2 production is proposed.
从反硝化细菌粪产碱杆菌S-6菌株中纯化并结晶出一种分子量为12,000的蓝色蛋白质，该蛋白质含有1个I型Cu2+原子，作为同一生物体含铜亚硝酸还原酶的失活因子。当该酶在还原剂如半胱氨酸和抗坏血酸存在下与催化量的蓝色蛋白质进行需氧孵育时，酶会发生失活。蓝色蛋白质作为该酶的直接电子供体，催化亚硝酸盐的还原，但在没有亚硝酸盐的情况下，酶还原的蓝色蛋白质系统会与氧气反应生成过氧化氢。提出了由于这种过氧化氢产生导致的酶自杀失活机制。
