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Ebbe Nordlander. Portrait.

Ebbe Nordlander

Professor

Ebbe Nordlander. Portrait.

An investigation of the peroxidase activity of Vitreoscilla hemoglobin

Author

  • Malin Kvist
  • Ekaterina Ryabova
  • Ebbe Nordlander
  • Leif Bülow

Summary, in English

In order to investigate the ability of the Vitreoscilla hemoglobin (VHb) to act as a peroxidase, the protein was overexpressed in Escerichia coli and purified using a 6xHis-tag. The peroxidase activity of VHb was studied using 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferrocene carboxylic acid (FcCOOH) dopamine and L-dopa as substrates. The effects of external agents such as pH, salt concentration/ionic strength, and the thermal stability of VHb on the catalytic activity were assessed. The optimum pH for VHb using ABTS as a substrate was estimated to be 6-7. The VHb protein proved to be stable up to 80 degrees C, as judged by its peroxidase activity. Furthermore, NaCl concentrations up to 100 mM did not exert any significant effect on the activity. The catalytic activity against ABTS and FcCOOH was similar to that measured for horseradish peroxidase, whereas in the case of the phenolic substrates dopamine and L-dopa the activity was several orders of magnitude lower. The Michaelis constants, K-m(H2O2), were in good agreement with the data for human and bovine hemoglobin. No activity could be detected for the negative controls lacking VHb. These results demonstrate that VHb exhibits peroxidase activity, a finding in line with the hypothesis that VHb has cellular functions beyond the role as an oxygen carrier.

Department/s

  • Pure and Applied Biochemistry
  • Department of Chemistry
  • Chemical Physics

Publishing year

2007

Language

English

Pages

324-334

Publication/Series

Journal of Biological Inorganic Chemistry

Volume

12

Issue

3

Document type

Journal article

Publisher

Springer

Topic

  • Biological Sciences
  • Atom and Molecular Physics and Optics

Keywords

  • peptide
  • peroxidase
  • protopoporphyrin IX
  • catalysis

Status

Published

ISBN/ISSN/Other

  • ISSN: 1432-1327