An investigation of the peroxidase activity of Vitreoscilla hemoglobin

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An investigation of the peroxidase activity of Vitreoscilla hemoglobin. / Kvist, Malin; Ryabova, Ekaterina; Nordlander, Ebbe; Bülow, Leif.

In: Journal of Biological Inorganic Chemistry, Vol. 12, No. 3, 2007, p. 324-334.

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TY - JOUR

T1 - An investigation of the peroxidase activity of Vitreoscilla hemoglobin

AU - Kvist, Malin

AU - Ryabova, Ekaterina

AU - Nordlander, Ebbe

AU - Bülow, Leif

N1 - The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Pure and Applied Biochemistry (LTH) (011001005), Chemical Physics (S) (011001060), Department of Chemistry (011001220)

PY - 2007

Y1 - 2007

N2 - 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.

AB - 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.

KW - peptide

KW - peroxidase

KW - protopoporphyrin IX

KW - catalysis

U2 - 10.1007/s00775-006-0190-x

DO - 10.1007/s00775-006-0190-x

M3 - Article

C2 - 17219165

VL - 12

SP - 324

EP - 334

JO - Journal of Biological Inorganic Chemistry

JF - Journal of Biological Inorganic Chemistry

SN - 1432-1327

IS - 3

ER -