Figure 1

Here we diagram the possible role GSTM-1 enzyme plays inside the mitochondrial matrix as mtDNA protector factor regarding damage caused by reactive species. The biological systems can produce these compounds by different pathways. One of the most important endogenous mechanisms is the respiratory chain, generating great levels of ROS during the O² reduction. Lipid peroxidation over the membrane lipoprotein, caused by ROS action, is another source of active compounds (HNE: 4-Hydroxynonenal, for example). Another important mechanism involved in ROS generation is the biotransformation of different exogenous compounds or xenobiotics by action of different XME.The ROS action into the cell could produce lesions in different mt compounds, such as lipids; damage different kinds of proteins, Pol-γ for example; damage the mtDNA directly by action of these active species on the bases, or indirectly by DNA replication with a faulty Pol-y that introduces errors. Altogether, those deleterious processes lead to genotoxic damage, as shown in the right side of the image. The left side shows the possible metabolic pathway of the GSTM-1 enzyme, promoting the elimination of reactive species and blocking their deleterious effect over the mt component. It is important to note the possible protective action of GSTM-1 over the mtDNA. The picture shows only a schematic pathway for the GSTM-1 enzyme; the other mitochondrial matrix events are simplified.