Denaturation of Cytochrome C Induced by Non-Thermal Plasma Irradiation

Abstract

Cytochrome c, a heme protein located in mitochondria of cell, has the electron transport function for it undergoes oxidation/reduction to transfer electrons between cytochrome c reductase and cytochrome c oxidase. Due to its location and function, cytochrome c is also a target of reactive oxygen species (ROS) in cells since mitochondria are the main place producing intracellular ROS. Because ionizing radiation can elicit significant ROS enhancement in cells, investigating the radiation-induced oxidative damage of cytochrome c is therefore an interesting issue. So far there have been some literatures reporting the oxidative damage of cytochrome c by ROS [1-3], but most of them focused on the modification of peptide moiety. In this work, non-thermal plasma [4] was employed to induce the oxidative damage on cytochrome c. Various oxidants including free radicals such as hydroxyl radical, superoxide radical and hydrogen peroxide were produced in solution during the plasma discharge. It was found that the protein was rapidly denatured/degraded by plasma discharge. By adding ROS scavengers it was confirmed that hydrogen peroxide was the main direct factor leading to the enzyme's denaturation. The results make us better understand the process and mechanism for the enzyme's oxidative damage and therefore may help us to find ways to protect cells from damage under oxidative stress conditions.This work was supported by the Foundation of the Natural Science of China (No.10975152), Hundred Talents Program of Chinese Academy of Sciences (CAS) and the Key Knowledge Innovation Project of CAS.[1] J. Kim et al., Free Radic Biol Med. 2008, 44, 1700-1711.[2] W. S. Zong, et al., Spectrochimica Acta Part A 2011, 78, 1581-1586.[3] N. H. Kim, et al., Mol. Cells, 2006, 22, 220-227.[4] Z. Ke, et al., Plasma Processes and Polymers (in press)