Fluorescence Spectroscopic and Thermodynamic Studies of Chlorophyll Containing Monolayers and Vesicles. Part I: Mixed Monolayers of Pheophytin A and Lecithin
Mixed monolayers of pheophytin a and α-ʟ-dimyristoyl lecithin (DML) are investigated on the water surface. The studies gain their special value from the simultaneous measurement of surface pressure and fluorescence intensity as a function of the covered area per molecule. A phase separation in the l...
| Published in: | Zeitschrift für Naturforschung C |
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| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | unknown |
| Published: |
Walter de Gruyter GmbH
1978
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1515/znc-1978-5-613 http://www.degruyter.com/view/j/znc.1978.33.issue-5-6/znc-1978-5-613/znc-1978-5-613.xml https://www.degruyter.com/document/doi/10.1515/znc-1978-5-613/pdf |
| Summary: | Mixed monolayers of pheophytin a and α-ʟ-dimyristoyl lecithin (DML) are investigated on the water surface. The studies gain their special value from the simultaneous measurement of surface pressure and fluorescence intensity as a function of the covered area per molecule. A phase separation in the liquid state of the monolayer is established. Phase 1 exists almost exclusively of pheophytin molecules. Phase 2 exists essentially of DML domains solubilizing pheophytin in a concentration of 15 mol%. During the DML main transition the pheophytin solubility decreases to about 2 mol%, the excess pheophytin being precipitated within the surface layer. During the pheophytin main transition an ordered structure below the surface layer is formed. A stabilizing interaction between the pheophytin domains and their environment is observed and discussed. A sharp fluorescence change at a pressure below 0.5 dyn/cm indicates another phase transition. It very probably involves an unwrapping of pheophytin from water molecules. |
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