title: Chlorophylls attached to lipid and protein globules, absorption and fluorescence spectra, photo-oxidation.
abstract: The precipitation of chlorophylls upon lipid and protein globules suspended in an aqueous buffer yields a partial model of photosynthetic membranes. The absorption and fluorescence spectra of the model are investigated as well as the photo-oxidation of the chlorophylls (bleaching) by dissolved oxygen. It is shown that pigment--pigment interactions occur in such systems, by (a) the appearance of absorption bands characteristic of crystalline or highly ordered chlorophyll at high pigment concentrations, (b) the chlorophyll a-type of fluorescence of systems containing chlorophyll a and chlorophyll b where the latter is selectively excited, and (c) the kinetics of photo-oxidation which suggest that chlorophylls can only be bleached when they are dimerized.
mesh_terms: D000818:Animals; D001665:Binding Sites; D002338:Carotenoids; D002417:Cattle; D002734:Chlorophyll; D005260:Female; D007700:Kinetics; D008055:Lipids; D008892:Milk; D008894:Milk Proteins; D010777:Photochemistry; D011485:Protein Binding; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry
chemical_list: D008055:Lipids; D008894:Milk Proteins; D002734:Chlorophyll; D002338:Carotenoids