Cabail Maria Zulema, Pacheco A Andrew
Department of Chemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, USA.
Inorg Chem. 2003 Jan 27;42(2):270-2. doi: 10.1021/ic025779n.
Hydroxylamine oxidoreductase (HAO) from the autotrophic bacterium Nitrosomonas europaea catalyzes the 4-e- oxidation of NH2-OH to NO2-. The e- are transferred from NH2OH to an unusual 5-coordinate heme known as P460, which is the active site of HAO, and from there to an array of seven c-type hemes. NO., generated by laser flash photolysis of N,N'-bis(carboxymethyl)-N,N'-dinitroso-1,4-phenylenediamine, is found to act as a 1-e- donor to HAO. Most likely NO. binds P460 to yield a [Fe(NO)]6 moiety, which then hydrolyzes to give the reduced enzyme and NO2-. The [Fe(NO)]6 moiety is also a plausible final intermediate in the oxidation of NH2OH.
自养细菌欧洲亚硝化单胞菌中的羟胺氧化还原酶（HAO）催化NH2-OH的4电子氧化生成NO2-。电子从NH2OH转移到一种不同寻常的五配位血红素，即P460，它是HAO的活性位点，然后从那里转移到一系列七个c型血红素。通过激光闪光光解N，N'-双（羧甲基）-N，N'-二亚硝基-1，4-苯二胺产生的NO·被发现可作为HAO的单电子供体。很可能NO·与P460结合生成[Fe(NO)]6部分，然后水解生成还原态酶和NO2-。[Fe(NO)]6部分也是NH2OH氧化过程中一个合理的最终中间体。
