Abstract
Singlet oxygen belongs to the reactive oxygen species (ROS). It has the ability to penetrate through cell membranes and quickly reacts with biomolecules.
Singlet oxygen is produced by activated phagocytes in photochemical reactions, during chemoexcitation and in many chemical and biochemical reactions. Singlet oxygen has positive and negative effects on the human body.
As positive properties are its ability to kill microbs, viruses, tumor cells, it acts as signal mechanism. In the reaction of antibody with antigen singlet oxygen is produced and it may have also a positive influence, it is increased in chronic inflammations.
Negative properties of singlet oxygen predominate. Scavengers of singlet oxygen are mainly proteins, oxidized proteins sometimes cannot be sufficiently removed inside the cells.
Some important enzymes can be inactivated. Other scavengers are histidine, uric acid, selenium and reduced glutathione.
Singlet oxygen oxidizes LDL-cholesterol, bilirubin and DNA, especially guanin. It damages cardiovascular system, increases the level of calcium, decreases SH-groups, initiats cardiac arrythmias.
Extracellulary produced singlet oxygen has cytotoxic effect to respirátory epithelial cells. Singlet oxygen inhibits the aggregation of thrombocytes, produces slow progressive neuronal degeneration.
In conclusion we can say, that in the human body the negative effects of singlet oxygen predominate the positive ones.