Anderson J R, Strumeyer D H, Pramer D
J Bacteriol. 1968 Jul;96(1):93-7. doi: 10.1128/jb.96.1.93-97.1968.
Peroxidase from the obligate chemosynthetic bacterium Nitrosomonas europaea was purified 1,500-fold, and its properties were examined. The enzyme had a molecular weight of 53,000 and exhibited characteristic absorption maxima at 410, 524, and 558 mmu. The optimal pH and temperature were 7.5 and 44 C, respectively. The peroxidase reaction had an energy of activation of 5,850 cal/mole and required a primary substrate (H(2)O(2)) concentration of 7 x 10(-6)m to proceed at half maximal velocity (K(m)). Reduced cytochrome, c,p-phenylenediamine and pyrogallol acted as hydrogen donors to the purified peroxidase-H(2)O(2) complex. Conditions most suitable for the chemical oxidation of ammonium by H(2)O(2) were determined. The reaction was rapid and produced nitrite but no nitrate. Hydroxylamine was not detected as an intermediate, but it could substitute for ammonium in the system. Neither the rate nor the extent of these reactions was influenced by purified peroxidase, and no evidence was obtained to support a conclusion that the enzyme performs a vital role in the transformation of ammonium to nitrite by N. europaea.
对专性化能合成细菌欧洲亚硝化单胞菌中的过氧化物酶进行了1500倍的纯化，并对其性质进行了研究。该酶的分子量为53000，在410、524和558毫微米处呈现特征性吸收峰。最适pH和温度分别为7.5和44℃。过氧化物酶反应的活化能为5850卡/摩尔，在半最大速度（K(m)）下进行反应需要7×10(-6)m的初级底物（H(2)O(2)）浓度。还原型细胞色素c、对苯二胺和连苯三酚作为纯化的过氧化物酶-H(2)O(2)复合物的氢供体。确定了最适合H(2)O(2)化学氧化铵的条件。该反应迅速，产生亚硝酸盐但不产生硝酸盐。未检测到羟胺作为中间产物，但它可以在该系统中替代铵。这些反应的速率和程度均不受纯化过氧化物酶的影响，也没有证据支持该酶在欧洲亚硝化单胞菌将铵转化为亚硝酸盐的过程中起关键作用这一结论。
