ACTION DE LA TEMPERATURE SUR LA DUREE DE VIE DE FLUORESCENCE ET LE RENDEMENT DE FLUORESCENCE DE LA C‐PHYCOCYANINE EN SOLUTION

Abstract— The influence of temperature on the fluorescence yield and lifetime (measured by a phase fluorimeter) of C‐hycocyanin in various forms of polymerization in solution, was studied over the temperature range 0–75°C. The temperature dependence of φ and φ below 50°C may be ascribed to an effect on internal conversion, with activation energy of 0.45. eV. Above 50°C, a large enhancement of is observed which may be due to the appearance of direct fluorescence from the sensitizer chromophores, the transfer efficiency between the two different chromo‐phores present in each monomer being decreased by protein denaturation. At room temperature, there is almost no difference between the lifetimes of the different polymers, whereas large differences between their fluorescence yields are observed. Therefore, a static quenching of the fluorescence of the chromophores by the solvent molecules may occur.