Biochemistry (Moscow)

, Volume 75, Issue 6, pp 744–751

Isolation and characterization of nitrate reductase from the halophilic sulfur-oxidizing bacterium Thioalkalivibrio nitratireducens

  • A. A. Filimonenkov
  • R. A. Zvyagilskaya
  • T. V. Tikhonova
  • V. O. Popov
Article

DOI: 10.1134/S000629791006009X

Cite this article as:
Filimonenkov, A.A., Zvyagilskaya, R.A., Tikhonova, T.V. et al. Biochemistry Moscow (2010) 75: 744. doi:10.1134/S000629791006009X

Abstract

A novel nitrate reductase (NR) was isolated from cell extract of the haloalkaliphilic bacterium Thioalkalivibrio nitratireducens strain ALEN 2 and characterized. This enzyme is a classical nitrate reductase containing molybdopterin cofactor in the active site and at least one iron-sulfur cluster per subunit. Mass spectrometric analysis showed high homology of NR with the catalytic subunit NarG of the membrane nitrate reductase from the moderately halophilic bacterium Halomonas halodenitrificans. In solution, NR exists as a monomer with a molecular weight of 130–140 kDa and as a homotetramer of about 600 kDa. The specific nitrate reductase activity of NR is 12 μmol/min per mg protein, the maximal values being observed within the neutral range of pH. Like other membrane nitrate reductases, NR reduces chlorate and is inhibited by azide and cyanide. It exhibits a higher thermal stability than most mesophilic enzymes.

Key words

Thioalkalivibrio nitratireducens haloalkaliphilic bacteria nitrate reductase NarG 

Abbreviations

HPLC

high performance liquid chromatography

MGD

molybdopterin guanine dinucleotide

Nap

periplasmic dissimilatory nitrate reductases

Nar

respiratory membrane-bound nitrate reductases

NarGHI

membrane-bound nitrate reductase composed of NarG, NarH, and NarI subunits

Nas

assimilatory nitrate reductase

NR

nitrate reductase from Thioalkalivibrio nitratireducens

PPB

potassium-phosphate buffer

Copyright information

© Pleiades Publishing, Ltd. 2010

Authors and Affiliations

  • A. A. Filimonenkov
    • 1
  • R. A. Zvyagilskaya
    • 1
  • T. V. Tikhonova
    • 1
  • V. O. Popov
    • 1
  1. 1.Bach Institute of BiochemistryRussian Academy of SciencesMoscowRussia

Personalised recommendations