Study of the Interaction Between Peroxynitrite and Hemoglobin

Abstract

Peroxynitrite (ONOO⁻), which is usually generated as a response of the immune system or in inflammatory processes, is a powerful oxidant species, while hemoglobin is an important peroxynitrite scavenger in vivo. In this work, we have studied the interaction between peroxynitrite and hemoglobin through an electrochemical method and UV-Vis spectroscopy. It is found that peroxynitrite, at a relatively high concentration level, may make the protein exhibit a concentration-dependent increase of its catalytic activity towards hydrogen peroxide, whereas peroxynitrite at low concentration will result in the slight decrease of the catalytic activity. Further studies reveal that the diversification of the enzymatic activity is ascribed to the different extent of tyrosine nitration and, accordingly, the spatial conformation of the protein.

Keywords:

• Electrochemistry
• hemoglobin
• nitration
• peroxidase activity
• peroxynitrite

This work is supported by the National Natural Science Foundation of China (Grants 90406005, 20575028) and the Program for New Century Excellent Talents in University, the Chinese Ministry of Education (NCET-04-0452).