Photolysis of incorporated benzophenone derivatives inside compressed lipid monolayers

Abstract

The goal of this work was to study the possibility of the occurrence of radical- type lipid peroxidation of the lipid constituents on biomembranes, in compressed monolayers, having lipoidal benzophenone photosensitizers incorporated. The triplets of the photosensitizer abstract allylic and doubly-allylic hydrogen atoms from anticonjugated moities of the lipid molecules. The results simultaneously confirmed the occurrence of H-abstraction (and so the initiation of the peroxidizing chain mechanism), and the absence of the formation of lipid peroxides. The reason lies in "cage effect": the highly restricted spacial area of compressed lipid monolayers limits the mobility of the created radicals (lipid radicals and ketyl radicals) and leads to their recombination, thus preventing the propagation step of the chain mechanism. With certain reservations it may be concluded that these results have a clear implication on real biomembranes: the structure of which is one of themain factors preventing the spread of the chain reaction, and the formation of lipid peroxides.

The Life of Pi Star: Exploring the Exciting and Forbidden Worlds of the Benzophenone Photophore

“…Indeed, the relative chemical inertness of the phospholipid bilayer can increase the lifetime of the reactive species; therefore, BP is particularly useful. Nonetheless, it should be noted that BP could more easily abstract H from allylic or doubly allylic hydrogen atoms from anticonjugated lipid molecules …”

“…Nonetheless, it should be noted that BP could more easily abstract H from allylic or doubly allylic hydrogen atoms from anticonjugated lipid molecules. 260 4.2.7.3.2. Bola-Lipid Probes.…”

“…This approach led to the identification of novel sites of BCL-2 family protein interaction and revealed an allosteric exposure of the C-terminal pocket as a result of N-terminal site triggering reveals a secondary BAD BH3-binding site. The most abundant cross-link, located between BAD pSAHB-2 Bpa-110 (260) and BCL-XLΔC Phe-105, and Phe-105 was identified as the crosslinked site by MS/MS analysis.…”