| Dynamic action of Carotenoids in Membranes |
| Paper ID : 1011-ISCH |
| Authors |
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Medhat Wahba Shafaa * Medical Biophysics Division, Physics Dept., Faculty of Science, Helwan University |
| Abstract |
| Carotenoids, found in cell membranes of plants and animals, act as important regulators of membrane properties. They can increase membrane rigidity and thermostability, and act as a barrier against oxygen and other small molecules. Carotenoids also play a role in photoprotection, particularly in chloroplasts, by stabilizing and protecting the lipid phase of the thylakoid membranes. Carotenoids, due to their unique structure, primarily orient themselves within the hydrophobic core of lipid membranes. Their orientation is influenced by the specific carotenoid's structure and whether it is polar or nonpolar. Nonpolar carotenoids like β-carotene tend to reside within the membrane's hydrocarbon region without a specific orientation, while polar carotenoids (xanthophylls) like zeaxanthin tend to position their polar groups at the membrane's polar interfaces (headgroups). Carotenoids dynamically alter membrane properties, influencing fluidity, rigidity, and thickness, due to their structural characteristics and interactions with lipids. They can increase or decrease membrane fluidity depending on the phase state and concentration, and also increase membrane rigidity and thickness. These effects can modulate various membrane-dependent processes, including those related to photosynthesis and antioxidant protection. |
| Keywords |
| Carotenoids, cell membranes, fluidity, rigidity, β-carotene , zeaxanthin |
| Status: Abstract Accepted (Oral Presentation) |