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Hemoglobin can nitrate itself and other proteins.
A Grzelak1, A Balcerczyk, A Mateja
1Department of Molecular Biophysics, University of Łódź, Poland.
Biochimica Et Biophysica Acta
|November 1, 2001
Summary
Human hemoglobin and hydrogen peroxide can nitrate proteins, including those in red blood cells. This pseudoperoxidase activity suggests hemoproteins may contribute to in vivo tyrosine nitration.
Area of Science:
- Biochemistry
- Protein Chemistry
- Redox Biology
Background:
- Tyrosine nitration is a post-translational modification implicated in various physiological and pathological processes.
- Hemoglobin, a major protein in red blood cells, possesses pseudoperoxidase activity.
- Nitrite and hydrogen peroxide are reactive species present in biological systems.
Purpose of the Study:
- To investigate the potential of human hemoglobin to induce tyrosine nitration.
- To explore the role of hemoglobin's pseudoperoxidase activity in protein nitration.
- To determine if erythrocyte membrane proteins are susceptible to nitration by hemoglobin.
Main Methods:
- Incubation of human hemoglobin with nitrite and hydrogen peroxide.
- Detection of nitrotyrosine residues using Western blotting.
- Assessing nitration in whole erythrocytes, with and without catalase inhibition.
Main Results:
- Hemoglobin incubation with nitrite and hydrogen peroxide led to autonitration and nitration of bovine serum albumin.
- Nitration was inhibited when hemoglobin was converted to the cyanmet form, confirming the role of pseudoperoxidase activity.
- Erythrocyte membrane proteins were nitrated, with enhanced nitration observed upon catalase inhibition.
Conclusions:
- Hemoglobin's pseudoperoxidase activity can directly cause tyrosine nitration.
- Erythrocyte membrane proteins are targets for hemoglobin-mediated nitration.
- Hemoproteins may contribute to endogenous tyrosine nitration in vivo.