| dc.description.abstract | The oxygen reactive species generated during the photooxidation of tyrosine sensitized by riboflavin were studied and the products formed were isolated. It was found that this process occurs preferently through a type I mechanism, which involves the direct interaction between the excited state of the sensitizer and tyrosine. The formation of O-2.-, H2O2 and .OH was detected along the photooxidative process. By changing H2O by D2O it could be established that O-1(2) has no significant role in the photooxidation of tyrosine sensitized by riboflavin. When a previously irradiated solution of tyrosine was applied to a Sephadex G-15 column, four fractions could be separated corresponding to products having hydrodynamic volumes larger than those of the reactants. By the use of C-14-tyrosine the aminoacidic origin of the products could be determined; one of them was identified as bityrosine, according to its fluorescence properties and H-1-NMR spectrum. | |
