title: Effects of gamma-radiation on the optical properties of aqueous lysozyme-polyinosinic-acid complexes.
abstract: The absorption of gamma-rays by dilute aqueous solutions of lysozyme and polyinosinic acid (poly I) causes significant increases in the light-scattering power of room temperature solutions in certain critical concentration regions. Light-scattering properties are unaltered by relatively large doses of radiation delivered to heated complexes. Prior irradiation of the poly I alone yields complexes whose light-scattering properties are the same as those of the unirradiated system. Studies of the radiation-induced absorbance changes of these complexes at 260 and 280 nm show behaviour indicative of the radiation chemistry of polynucleotide rather than of lysozyme. From the evidence available, it is postulated that most of the damage is to the poly I rather than lysozyme in the complexes. Increases in light-scattering and dissymmetry are attributed to unwinding of the multi-stranded polynucleotide. The role of water in the formation and radiation sensitivity of the complexes is discussed.
mesh_terms: D003037:Cobalt Radioisotopes; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D007291:Inosine Monophosphate / Q000528:radiation effects*; D007292:Inosine Nucleotides / Q000528:radiation effects*; D008027:Light; D009113:Muramidase / Q000528:radiation effects*; D011830:Radiation Effects; D012542:Scattering, Radiation; D012996:Solutions; D014867:Water
chemical_list: D003037:Cobalt Radioisotopes; D007292:Inosine Nucleotides; D012996:Solutions; D014867:Water; D007291:Inosine Monophosphate; D009113:Muramidase