Interaction of nitroaromatic radiosensitizers with irradiated polyadenylic acid as measured by an indirect immunochemical assay with specificity for the 8,5'-cycloadenosine moiety.
The relative reactivity of a series of nitroaromatic radiosensitizers toward the C(5') radical intermediate leading to 8,5'-cycloadenosine formation in deoxygenated solutions of irradiated polyadenylic acid (poly A) was assessed using standard competition kinetic analysis. Formation of 8,5'-cycloadenosine was assayed by an indirect, competitive, enzyme-linked immunosorbent assay (ELISA) described in an earlier report. In the absence of oxygen, the nitroaromatics inhibit 8,5'-cyclonucleoside formation in a way which generally increases with radiosensitizer electron affinity. Although hydroxyl radical scavenging by the nitroaromatics may account for a relatively small decrease in 8,5'-cyclonucleoside formation, the data suggest that oxidation of the C(5') radical intermediate is the more plausible explanation for the decreased yield of the 8,5'-cyclonucleoside with increasing nitroaromatic electron affinity.
Fuciarelli
A F
AF
Mele
F G
FG
Raleigh
J A
JA
D000241:Adenosine / Q000031:analogs & derivatives / Q000276:immunology; D055598:Chemical Phenomena; D002621:Chemistry; D004249:DNA Damage; D005609:Free Radicals; D005720:Gamma Rays; D007158:Immunologic Techniques; D008920:Misonidazole; D009578:Nitrobenzenes; D011061:Poly A / Q000528:radiation effects*; D011838:Radiation-Sensitizing Agents; D013329:Structure-Activity Relationship
D005609:Free Radicals; D009578:Nitrobenzenes; D011838:Radiation-Sensitizing Agents; D011061:Poly A; C025132:8,5'-cycloadenosine; D008920:Misonidazole; D000241:Adenosine