@entity6337 mechanism of a XXXX dye in human red cell membranes and isolated @entity19 mitochondria.

@entity2769 @entity6337 @entity6453 @entity19 @entity5 @entity26 @entity8794 @entity4360 @entity2768 @entity2507 @entity519 @entity71040 @entity224 @entity3503
The @entity6337 mechanism of a @entity71040 dye, @entity8794 (EDKC+), has been studied in RBC membranes and isolated mitochondria. Lipophilic, positively charged dyes, such as EDKC+, may be useful as tumor-cell-selective, light-activated cytotoxic agents. Exposure of the RBC membranes to 700-nm light and EDKC+ inhibited membrane @entity4360 and photodecomposed EDKC+ in air-purged but not @entity3503 -purged samples. Photoinactivation of @entity4360 was the same in @entity2768 as in @entity2507 and was not quenched by @entity224 dismutase. Ascorbate and @entity2769 (10 mM) quenched or slightly enhanced, respectively, the inactivation. In argon-purged samples containing @entity6453 , EDKC+ photodecomposed, but @entity4360 activity was unaffected. The mechanism may involve electron transfer to @entity26 and subsequent formation of toxic photoproducts from EDKC+. In contrast, exposure of @entity19 mitochondria to EDKC+ and 700-nm light caused inhibition of mitochondrial respiration in both the presence and absence of @entity26 . The photodecomposition of EDKC+ correlated with inhibition of respiration. Thus, the @entity6337 of EDKC+ in mitochondria may be due to electron transfer from photoexcited EDKC+ to @entity26 and electron acceptors in the membrane. These studies indicate that dyes such as EDKC+ may be useful for photochemotherapy of @entity519 regions in @entity5 .
