title: Extracellular lumazine from aggregating Dictyostelium discoideum cells. Influence of pH on its fluorescence.
abstract: Lumazine has been demonstrated to be one of the two main compounds responsible for the extracellular fluorescence linked with the aggregation ability of Dictyostelium discoideum, strain Ax-2. The other compound, also having lumazine properties, is, however, different from the 7-hydroxylumazine proposed previously. The influence of pH on the fluorescence of lumazine was studied. The possible use of extracellular pteridines as pH markers was stressed and a method for the determination of the amount of "lumazine equivalents" in the extracellular medium of aggregating D. discoideum cells is elaborated.
mesh_terms: D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000032:analysis*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004023:Dictyostelium / Q000032:analysis*; D005453:Fluorescence; D006863:Hydrogen-Ion Concentration; D008164:Luminescent Proteins; D013050:Spectrometry, Fluorescence / Q000379:methods
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D008164:Luminescent Proteins; C026648:lumazine protein, Photobacterium