Photomodification of Hp accumulated in erythrocyte cell ghosts

摘要

Abstract: The changes of the fluorescence emission spectra detected after the irradiation of buffered Hp solutions (C equals 10$+$MIN@4$/ M) in a suspension of resealed erythrocyte cell ghosts (ECG) showed that the emission decay of Hp incorporated in ECG is faster than that of Hp in aqueous medium. The disappearance of emission bands at 634 nm and 700 nm and the development of a new emission band at 642 nm precede a period when the photobleaching of aqueous Hp becomes dominant. Besides the possible photodestruction of Hp, these spectroscopic changes might be related to the formation of a photoproduct and the light- induced relocalization of Hp in ECG. A fraction of aqueous Hp is transformed to the photoproduct with emission band at around 640 nm. It is likely that the HP fraction incorporated in ECG mostly undergo a relocalization, which may lead to a strong interaction of Hp with proteins and lipids of ECG resulting in a disappearance of characteristic porphyrin emission bands and a decrease of the emission capacity. However, a possible formation of a small amount of the new photoproduct (similar to that formed in aqueous medium) and photodestruction of Hp could not be excluded. !12