Tài liệu Báo cáo y học: "Autofluorescent Proteins as Photosensitizer in Eukaryonte"

Without doubt oxygen is considered as a pivotal element for the existence of aerobic life on earth. But in the last forty years, evidences indicated increasingly Janus-faced behaviors of this element1-3 for the following reasons: Under certain conditions, oxygen may produce reactive species, even free radicals responsible for different molecular cell response like cellular stress4,5. Despite all undesired consequences provoked by these oxygen’s properties, these facts were not yet in the focus of the scientific discussion and still poorly understood during the last few years as illustrated comprehensively6. The paradox of the oxygen atom depending on its peculiar electronic structure is the existence as a free radical, because the outer valence shell contains one unpaired electron. After combining two oxygen atoms to form molecular oxygen no formation of a spin-pair is possible and resulting in a formation of a bi-radical which allows a stepwise one electron reduction as depicted in Figure 1.