title: Peroxidase and photoprotective activities of magnesium protoporphyrin IX.
abstract: Magnesium-protoporphyrin IX (Mg-PPn), which is formed through chelation of protoporphyrin IX (PPn) with Mg ion by Mg chelatase, is the first intermediate for the (bacterio)chlorophyll biosynthetic pathway. Interestingly, Mg-PPn provides peroxidase activity (approximately 4 × 10(-2) units/micrometer) detoxifying H2O2 in the presence of electron donor(s). The peroxidase activity was not detected unless PPn was chelated with Mg ion. Mg-PPn was found freely diffusible through the membrane of Escherichia coli and Vibrio vulnificus, protecting the cells from H2O2. Furthermore, unlike photosensitizers such as tetracycline and PPn, Mg-PPn did not show any phototoxicity, but rather it protected cell from ultraviolet (UV)-A-induced stress. Thus, the exogenous Mg-PPn could be used as an antioxidant and a UV block to protect cells from H2O2 stress and UV-induced damage.
authors: Department of Life Science and Basic Science Institute for Cell Damage Control, Sogang University, Seoul 121-742, Republic of Korea.
authors: Eui-Jin
authors: EJ
authors: Kim
authors: Eun-Kyoung
authors: EK
authors: Oh
authors: Jeong K
authors: JK
authors: Lee
mesh_terms: D002462:Cell Membrane / Q000378:metabolism; D002614:Chelating Agents / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism / Q000528:radiation effects; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000633:toxicity; D008274:Magnesium / Q000378:metabolism*; D009195:Peroxidase / Q000378:metabolism*; D011524:Protoporphyrins / Q000378:metabolism*; D014466:Ultraviolet Rays; D041261:Vibrio vulnificus / Q000378:metabolism / Q000528:radiation effects
chemical_list: D002614:Chelating Agents; D011524:Protoporphyrins; C039629:magnesium protoporphyrin; D006861:Hydrogen Peroxide; C028025:protoporphyrin IX; D009195:Peroxidase; D008274:Magnesium