STUDIES ON THE EFFECTS OF IRRADIATION OF CELLULAR PARTICULATES. III. THE EFFECT OF COMBINED RADIATION TREATMENTS ON PHOSPHORYLATION

Data are presented which show that ultraviolet radiation in the 2600 Å region inactivates oxidative phosphorylation. The addition of co-factors and the exposure to light of the preparations failed to reactivate the phosphorylation after treatment with ultraviolet. Treatment with infrared radiation and treatment with combined infrared and ultraviolet, infrared and gamma, and ultraviolet and gamma radiation failed to show any alteration in the normal inactivation patterns found with treatment with ultraviolet or gamma radiation alone. These data suggest that both ionizing and non-ionizing ultraviolet radiations damage cells, at least in part, by inactivation of oxidative phosphorylation. However, these data do not give any clue to the mechanism of action of combined radiations in altering the chromosomal structure of cells.