Yamanaka T, Shinra M, Takahashi K, Shibasaka M
J Biochem. 1979 Oct;86(4):1101-8. doi: 10.1093/oxfordjournals.jbchem.a132604.
Hydroxylamine oxidoreductase [EC 1.7.3.4] of Nitrosomonas europaea was purified to an electrophoretically homogeneous state and some of its properties were studied. The molecular weight of the enzyme as determined by gel filtration on Sephadex G150 and by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate is 175,000-180,000, while the minimum molecular weight per heme determined from the dry weight and heme content is 17,500. The enzyme is a C-type cytochrome; its reduced form shows absorption peaks at 418 (gamma peak), 521 (beta peak), 553 (alpha peak), and 460 nm (due to an unidentified chromophore). Although the alpha peak at 553 nm has a shoulder at 559 nm, the enzyme does not posses protoheme or a cytochrome b subunit. It seems likely that the enzyme molecule possess heme c molecules in different states. The enzyme reacts rapidly with various eukaryotic cytochromes c, but does not react with "bacterial-type" cytochromes c. Although the enzyme does not react with cytochrome c-552 (N. europaea), another C-type cytochrome of the organism, cytochrome c-554 (N. europaea) acts as an electron acceptor for the enzyme.
欧洲亚硝化单胞菌的羟胺氧化还原酶[EC 1.7.3.4]被纯化至电泳纯状态，并对其一些性质进行了研究。通过在Sephadex G150上进行凝胶过滤以及在十二烷基硫酸钠存在下进行聚丙烯酰胺凝胶电泳测定，该酶的分子量为175,000 - 180,000，而根据干重和血红素含量确定的每个血红素的最小分子量为17,500。该酶是一种C型细胞色素；其还原形式在418（γ峰）、521（β峰）、553（α峰）和460 nm（由于一种未鉴定的发色团）处显示吸收峰。尽管553 nm处的α峰在559 nm处有一个肩峰，但该酶不具有原血红素或细胞色素b亚基。酶分子似乎可能拥有处于不同状态的血红素c分子。该酶能与各种真核细胞色素c快速反应，但不与“细菌型”细胞色素c反应。尽管该酶不与细胞色素c - 552（欧洲亚硝化单胞菌）反应，该菌的另一种C型细胞色素，但细胞色素c - 554（欧洲亚硝化单胞菌）可作为该酶的电子受体。
