期刊
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS
卷 1837, 期 3, 页码 375-384出版社
ELSEVIER
DOI: 10.1016/j.bbabio.2014.01.001
关键词
NOR; NO reduction; Enzyme kinetics; Electrochemistry
资金
- Fundacao para a Ciencia e Tecnologia [SFRH/BD/39009/2007, PDTC/QUI/64638/2006, PDCT/QUI-BIOQ/1/6481/2010]
- FCT/MEC [PEst-C/EQB/LA0006/2013]
- Fundação para a Ciência e a Tecnologia [SFRH/BD/39009/2007] Funding Source: FCT
Nitric oxide reductase (NOR) from denitrifying bacteria is an integral membrane protein that catalyses the two electron reduction of NO to N2O, as part of the denitrification process, being responsible for an exclusive reaction, the N-N bond formation, the key step of this metabolic pathway. Additionally, this class of enzymes also presents residual oxidoreductase activity, reducing O-2 to H2O in a four electron/proton reaction. In this work we report, for the first time, steady-state kinetics with the Rseudomonas nautica NOR, either in the presence of its physiological electron donor (cyt.C-552) or immobilised on a graphite electrode surface, in the presence of its known substrates, namely NO or O-2. The obtained results show that the enzyme has high affinity for its natural substrate, NO, and different kinetic profiles according to the electron donor used. The kinetic data, as shown by the pH dependence, is modelled by ionisable amino acid residues nearby the di-nuclear catalytic site. The catalytic mechanism is revised and a mononitrosyl-non-heme Fe complex (Fe-B(II)-NO) species is favoured as the first catalytic intermediate involved on the NO reduction. (C) 2014 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据