title: Transverse motion of chlorophyll derivatives in phospholipid bilayers.
abstract: Chlorophyll derivatives were synthesized with spin labels attached to the porphyrin ring. These labels were incorporated into egg phosphatidylcholine vesicles in order to estimate the transbilayer motion (flip-flop) of this class of photosynthetic pigments. Using the ascorbate reduction method, the upper limit to the spin label half-life is tau 1/2 approximately 4 min at 0 degrees C. The flip-flop rate is rapid compared to that of a phospholipid spin label under the same conditions. The presence or absence of magnesium in the center of the porphyrin ring had no measurable effect on the flip-flop rate.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D002734:Chlorophyll; D004578:Electron Spin Resonance Spectroscopy; D008051:Lipid Bilayers; D010743:Phospholipids; D013113:Spin Labels
chemical_list: D008051:Lipid Bilayers; D010743:Phospholipids; D013113:Spin Labels; D002734:Chlorophyll